v3.25.2
Shareholder Report
 12 Months Ended
May 31, 2025
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSR
Amendment Flag false
Registrant Name Columbia Funds Series Trust II
Entity Central Index Key 0001352280
Entity Investment Company Type N-1A
Document Period End Date May 31, 2025
Columbia Mortgage Opportunities Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Columbia Mortgage Opportunities Fund
Class Name Class A
Trading Symbol CLMAX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Columbia Mortgage Opportunities Fund (the Fund) for the period of June 1, 2024 to May 31, 2025.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at
columbiathreadneedleus.com/resources/literature
. You can also request more information by contacting us at
1-800-345-6611.
Additional Information Phone Number 1-800-345-6611
Additional Information Website columbiathreadneedleus.com/resources/literature
Expenses [Text Block]
What were the Fund costs for the reporting period?
(Based on a hypothetical $10,000 investment)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Class A
$
112		1.06
%
Expenses Paid, Amount $ 112
Expense Ratio, Percent 1.06%
Factors Affecting Performance [Text Block]
Management's Discussion of Fund Performance
The performance of Class A shares for the period presented is shown in the Average Annual Total Returns table.
Top Performance Contributors
Interest rate positioning
| The Fund’s positioning with respect to interest rates contributed most to relative and absolute outperformance. Specifically, the Fund had an above-benchmark stance with respect to duration and corresponding interest rate sensitivity as short- and intermediate-term U.S. Treasury yields moved lower over the period. The Fund’s rate positioning also benefitted from a steepening yield curve over the period.
Non-agency residential mortgage-backed securities
| Non-agency residential mortgage-backed securities drove relative (the benchmark does not hold these securities) and absolute outperformance as housing fundamentals remained strong and borrower delinquencies remained low.
Agency residential mortgage-backed securities
| Performance for the Fund’s agency passthrough and collateralized mortgage obligation (CMO) holdings gained against a backdrop of falling interest rates and a steepening yield curve.
Top Performance Detractors
There were no material detractors to Fund performance during the period.
Performance Past Does Not Indicate Future [Text] The Fund's past performance is not a good predictor of the Fund's future performance.
Line Graph [Table Text Block]
Fund Performance - Growth of 10K
Average Annual Return [Table Text Block]
Average Annual Total Returns (%)1 year5 years10 years
Class A (excluding sales charges)12.793.513.54
Class A (including sales charges)9.422.883.22
FTSE One-Month U.S. Treasury Bill Index4.902.761.92
Bloomberg U.S. Aggregate Bond Index5.46(0.90
)
1.49
No Deduction of Taxes [Text Block] Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares.
Updated Performance Information Location [Text Block] Visit
columbiathreadneedleus.com/investment-products/mutual-funds
for more recent performance information.
Net Assets $ 2,180,670,766
Holdings Count | Holding 445
Advisory Fees Paid, Amount $ 14,345,650
Investment Company, Portfolio Turnover 706.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,180,670,766
Total number of portfolio holdings
445
Management services fees
(represents 0.64% of Fund average net assets)
$
14,345,650
Portfolio turnover for the reporting period
706%
Portfolio turnover for the reporting period excluding to be announced (TBA) securities
26%
Holdings [Text Block]
Graphical Representation of Fund
 
Holdings
The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change.
Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
Derivative Exposure
Long
Credit Risk8.2
%
Interest Rate Risk110.7
%
Short
Credit Risk4.6
%
Interest Rate Risk283.6
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
Credit Quality Explanation [Text Block] Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
Columbia Mortgage Opportunities Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Columbia Mortgage Opportunities Fund
Class Name Class C
Trading Symbol CLMCX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Columbia Mortgage Opportunities Fund (the Fund) for the period of June 1, 2024 to May 31, 2025.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at
columbiathreadneedleus.com/resources/literature
. You can also request more information by contacting us at
1-800-345-6611.
Additional Information Phone Number 1-800-345-6611
Additional Information Website columbiathreadneedleus.com/resources/literature
Expenses [Text Block]
What were the Fund costs for the reporting period?
(Based on a hypothetical $10,000 investment)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Class C
$
191		1.81
%
Expenses Paid, Amount $ 191
Expense Ratio, Percent 1.81%
Factors Affecting Performance [Text Block]
Management's Discussion of Fund Performance
The performance of Class C shares for the period presented is shown in the Average Annual Total Returns table.
Top Performance Contributors
Interest rate positioning
| The Fund’s positioning with respect to interest rates contributed most to relative and absolute outperformance. Specifically, the Fund had an above-benchmark stance with respect to duration and corresponding interest rate sensitivity as short- and intermediate-term U.S. Treasury yields moved lower over the period. The Fund’s rate positioning also benefitted from a steepening yield curve over the period.
Non-agency residential mortgage-backed securities
| Non-agency residential mortgage-backed securities drove relative (the benchmark does not hold these securities) and absolute outperformance as housing fundamentals remained strong and borrower delinquencies remained low.
Agency residential mortgage-backed securities
| Performance for the Fund’s agency passthrough and collateralized mortgage obligation (CMO) holdings gained against a backdrop of falling interest rates and a steepening yield curve.
Top Performance Detractors
There were no material detractors to Fund performance during the period.
Performance Past Does Not Indicate Future [Text] The Fund's past performance is not a good predictor of the Fund's future performance.
Line Graph [Table Text Block]
Fund Performance - Growth of 10K
Average Annual Return [Table Text Block]
Average Annual Total Returns (%)1 year5 years10 years
Class C (excluding sales charges)11.822.712.75
Class C (including sales charges)10.82 2.71 2.75
FTSE One-Month U.S. Treasury Bill Index4.902.761.92
Bloomberg U.S. Aggregate Bond Index5.46 (0.90
)
1.49
No Deduction of Taxes [Text Block] Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares.
Updated Performance Information Location [Text Block] Visit
columbiathreadneedleus.com/investment-products/mutual-funds
for more recent performance information.
Net Assets $ 2,180,670,766
Holdings Count | Holding 445
Advisory Fees Paid, Amount $ 14,345,650
Investment Company, Portfolio Turnover 706.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,180,670,766
Total number of portfolio holdings
445
Management services fees
(represents 0.64% of Fund average net assets)
$
14,345,650
Portfolio turnover for the reporting period
706%
Portfolio turnover for the reporting period excluding to be announced (TBA) securities
26%
Holdings [Text Block]
Graphical Representation of Fund
 
Holdings
The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change.
Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
Derivative Exposure
Long
Credit Risk8.2
%
Interest Rate Risk110.7
%
Short
Credit Risk4.6
%
Interest Rate Risk283.6
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
Credit Quality Explanation [Text Block] Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
Columbia Mortgage Opportunities Fund - Institutional Class  
Shareholder Report [Line Items]  
Fund Name Columbia Mortgage Opportunities Fund
Class Name Institutional Class
Trading Symbol CLMZX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Columbia Mortgage Opportunities Fund (the Fund) for the period of June 1, 2024 to May 31, 2025.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at
columbiathreadneedleus.com/resources/literature
. You can also request more information by contacting us at
1-800-345-6611.
Additional Information Phone Number 1-800-345-6611
Additional Information Website columbiathreadneedleus.com/resources/literature
Expenses [Text Block]
What were the Fund costs for the reporting period?
(Based on a hypothetical $10,000 investment)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Institutional Class
$
86		0.81
%
Expenses Paid, Amount $ 86
Expense Ratio, Percent 0.81%
Factors Affecting Performance [Text Block]
Management's Discussion of Fund Performance
The performance of Institutional Class shares for the period presented is shown in the Average Annual Total Returns table.
Top Performance Contributors
Interest rate positioning
| The Fund’s positioning with respect to interest rates contributed most to relative and absolute outperformance. Specifically, the Fund had an above-benchmark stance with respect to duration and corresponding interest rate sensitivity as short- and intermediate-term U.S. Treasury yields moved lower over the period. The Fund’s rate positioning also benefitted from a steepening yield curve over the period.
Non-agency residential mortgage-backed securities
| Non-agency residential mortgage-backed securities drove relative (the benchmark does not hold these securities) and absolute outperformance as housing fundamentals remained strong and borrower delinquencies remained low.
Agency residential mortgage-backed securities
| Performance for the Fund’s agency passthrough and collateralized mortgage obligation (CMO) holdings gained against a backdrop of falling interest rates and a steepening yield curve.
Top Performance Detractors
There were no material detractors to Fund performance during the period.
Performance Past Does Not Indicate Future [Text] The Fund's past performance is not a good predictor of the Fund's future performance.
Line Graph [Table Text Block]
Fund Performance - Growth of 10K
Average Annual Return [Table Text Block]
Average Annual Total Returns (%)1 year5 years10 years
Institutional Class12.943.753.78
FTSE One-Month U.S. Treasury Bill Index4.902.761.92
Bloomberg U.S. Aggregate Bond Index5.46(0.90
)
1.49
No Deduction of Taxes [Text Block] Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares.
Updated Performance Information Location [Text Block] Visit
columbiathreadneedleus.com/investment-products/mutual-funds
for more recent performance information.
Net Assets $ 2,180,670,766
Holdings Count | Holding 445
Advisory Fees Paid, Amount $ 14,345,650
Investment Company, Portfolio Turnover 706.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,180,670,766
Total number of portfolio holdings
445
Management services fees
(represents 0.64% of Fund average net assets)
$
14,345,650
Portfolio turnover for the reporting period
706%
Portfolio turnover for the reporting period excluding to be announced (TBA) securities
26%
Holdings [Text Block]
Graphical Representation of Fund
 
Holdings
The tables below show the investment makeup of the Fund represented as a percentage of F
u
nd net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change.
Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
Derivative Exposure
Long
Credit Risk8.2
%
Interest Rate Risk110.7
%
Short
Credit Risk4.6
%
Interest Rate Risk283.6
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
Credit Quality Explanation [Text Block] Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
Columbia Mortgage Opportunities Fund - Institutional 2 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Mortgage Opportunities Fund
Class Name Institutional 2 Class
Trading Symbol CLMVX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Columbia Mortgage Opportunities Fund (the Fund) for the period of June 1, 2024 to May 31, 2025.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at
columbiathreadneedleus.com/resources/literature
. You can also request more information by contacting us at
1-800-345-6611.
Additional Information Phone Number 1-800-345-6611
Additional Information Website columbiathreadneedleus.com/resources/literature
Expenses [Text Block]
What were the Fund costs for the reporting period?
(Based on a hypothetical $10,000 investment)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Institutional 2 Class
$
82		0.77
%
Expenses Paid, Amount $ 82
Expense Ratio, Percent 0.77%
Factors Affecting Performance [Text Block]
Management's Discussion of Fund Performance
The performance of Institutional 2 Class shares for the period presented is shown in the Average Annual Total Returns table.
Top Performance Contributors
Interest rate positioning
| The Fund’s positioning with respect to interest rates contributed most to relative and absolute outperformance. Specifically, the Fund had an above-benchmark stance with respect to duration and corresponding interest rate sensitivity as short- and intermediate-term U.S. Treasury yields moved lower over the period. The Fund’s rate positioning also benefitted from a steepening yield curve over the period.
Non-agency residential mortgage-backed securities
| Non-agency residential mortgage-backed securities drove relative (the benchmark does not hold these securities) and absolute outperformance as housing fundamentals remained strong and borrower delinquencies remained low.
Agency residential mortgage-backed securities
| Performance for the Fund’s agency passthrough and collateralized mortgage obligation (CMO) holdings gained against a backdrop of falling interest rates and a steepening yield curve.
Top Performance Detractors
There were no material detractors to Fund performance during the period.
Performance Past Does Not Indicate Future [Text] The Fund's past performance is not a good predictor of the Fund's future performance.
Line Graph [Table Text Block]
Fund Performance - Growth of 10K
Average Annual Return [Table Text Block]
Average Annual Total Returns (%)1 year5 years10 years
Institutional 2 Class13.013.773.82
FTSE One-Month U.S. Treasury Bill Index4.902.761.92
Bloomberg U.S. Aggregate Bond Index5.46(0.90
)
1.49
No Deduction of Taxes [Text Block] Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares.
Updated Performance Information Location [Text Block] Visit
columbiathreadneedleus.com/investment-products/mutual-funds
for more recent performance information.
Net Assets $ 2,180,670,766
Holdings Count | Holding 445
Advisory Fees Paid, Amount $ 14,345,650
Investment Company, Portfolio Turnover 706.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,180,670,766
Total number of portfolio holdings
445
Management services fees
(represents 0.64% of Fund average net assets)
$
14,345,650
Portfolio turnover for the reporting period
706%
Portfolio turnover for the reporting period excluding to be announced (TBA) securities
26%
Holdings [Text Block]
Graphical Representation of Fund
 
Holdings
The tables below show the investment makeup of the Fund represented as a percentage of
Fu
nd net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change.
Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
Derivative Exposure
Long
Credit Risk8.2
%
Interest Rate Risk110.7
%
Short
Credit Risk4.6
%
Interest Rate Risk283.6
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
Credit Quality Explanation [Text Block] Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
Columbia Mortgage Opportunities Fund - Institutional 3 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Mortgage Opportunities Fund
Class Name Institutional 3 Class
Trading Symbol CMOYX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Columbia Mortgage Opportunities Fund (the Fund) for the period of June 1, 2024 to May 31, 2025.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at
columbiathreadneedleus.com/resources/literature
. You can also request more information by contacting us at
1-800-345-6611.
Additional Information Phone Number 1-800-345-6611
Additional Information Website columbiathreadneedleus.com/resources/literature
Expenses [Text Block]
What were the Fund costs for the reporting period?
(Based on a hypothetical $10,000 investment)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Institutional 3 Class
$
76		0.72
%
Expenses Paid, Amount $ 76
Expense Ratio, Percent 0.72%
Factors Affecting Performance [Text Block]
Management's Discussion of Fund Performance
The performance of Institutional 3 Class shares for the period presented is shown in the Average Annual Total Returns table.
Top Performance Contributors
Interest rate positioning
| The Fund’s positioning with respect to interest rates contributed most to relative and absolute outperformance. Specifically, the Fund had an above-benchmark stance with respect to duration and corresponding interest rate sensitivity as short- and intermediate-term U.S. Treasury yields moved lower over the period. The Fund’s rate positioning also benefitted from a steepening yield curve over the period.
Non-agency residential mortgage-backed securities
| Non-agency residential mortgage-backed securities drove relative (the benchmark does not hold these securities) and absolute outperformance as housing fundamentals remained strong and borrower delinquencies remained low.
Agency residential mortgage-backed securities
| Performance for the Fund’s agency passthrough and collateralized mortgage obligation (CMO) holdings gained against a backdrop of falling interest rates and a steepening yield curve.
Top Performance Detractors
There were no material detractors to Fund performance during the period.
Performance Past Does Not Indicate Future [Text] The Fund's past performance is not a good predictor of the Fund's future performance.
Line Graph [Table Text Block]
Fund Performance - Growth of 10K
Average Annual Return [Table Text Block]
Average Annual Total Returns (%)1 year5 years10 years
Institutional 3
Class
(a)
13.043.843.82
FTSE One-Month U.S. Treasury Bill Index4.902.761.92
Bloomberg U.S. Aggregate Bond Index5.46(0.90
)
1.49
(a)
The returns shown for periods prior to March 1, 2017 (including Since Fund Inception returns, if shown) include the returns of Class A. These returns are adjusted to reflect any higher class-related operating expenses of the newer share classes, as applicable. Please visit
columbiathreadneedleus.com/investment-products/mutual-funds/appended-performance
for more information.
No Deduction of Taxes [Text Block] Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares.
Updated Performance Information Location [Text Block] Visit
columbiathreadneedleus.com/investment-products/mutual-funds
for more recent performance information.
Net Assets $ 2,180,670,766
Holdings Count | Holding 445
Advisory Fees Paid, Amount $ 14,345,650
Investment Company, Portfolio Turnover 706.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,180,670,766
Total number of portfolio holdings
445
Management services fees
(represents 0.64% of Fund average net assets)
$
14,345,650
Portfolio turnover for the reporting period
706%
Portfolio turnover for the reporting period excluding to be announced (TBA) securities
26%
Holdings [Text Block]
Graphical Representation of Fund
 
Holdings
The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Deriv
ativ
es are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change.
Derivative Exposure
Long
Credit Risk8.2
%
Interest Rate Risk110.7
%
Short
Credit Risk4.6
%
Interest Rate Risk283.6
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
Credit Quality Explanation [Text Block] Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
Columbia Mortgage Opportunities Fund - Class S  
Shareholder Report [Line Items]  
Fund Name Columbia Mortgage Opportunities Fund
Class Name Class S
Trading Symbol CLMDX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Columbia Mortgage Opportunities Fund (the Fund) for the period of October 2, 2024 to May 31, 2025.
Shareholder Report Annual or Semi-Annual annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at
columbiathreadneedleus.com/resources/literature
. You can also request more information by contacting us at
1-800-345-6611.
Additional Information Phone Number 1-800-345-6611
Additional Information Website columbiathreadneedleus.com/resources/literature
Expenses [Text Block]
What were the Fund costs for the reporting period?
(Based on a hypothetical $10,000 investment)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Class S
$
54
(a)
0.81
%
(b)
(a)
Based on operations from October 2, 2024 (commencement of operations) through the stated period end. Had the class been open for the entire reporting period, expenses shown in the table above would have been higher.
(b)
Annualized.
Expenses Paid, Amount $ 54 [1]
Expense Ratio, Percent 0.81% [2]
Factors Affecting Performance [Text Block]
Management's Discussion of Fund Performance
The performance of Class S shares for the period presented is shown in the Average Annual Total Returns table.
Top Performance Contributors
Interest rate positioning
| The Fund’s positioning with respect to interest rates contributed most to relative and absolute outperformance. Specifically, the Fund had an above-benchmark stance with respect to duration and corresponding interest rate sensitivity as short- and intermediate-term U.S. Treasury yields moved lower over the period. The Fund’s rate positioning also benefitted from a steepening yield curve over the period.
Non-agency residential mortgage-backed securities
| Non-agency residential mortgage-backed securities drove relative (the benchmark does not hold these securities) and absolute outperformance as housing fundamentals remained strong and borrower delinquencies remained low.
Agency residential mortgage-backed securities
| Performance for the Fund’s agency passthrough and collateralized mortgage obligation (CMO) holdings gained against a backdrop of falling interest rates and a steepening yield curve.
Top Performance Detractors
There were no material detractors to Fund performance during the period.
Performance Past Does Not Indicate Future [Text] The Fund's past performance is not a good predictor of the Fund's future performance.
Line Graph [Table Text Block]
Fund Performance - Growth of 10K
Average Annual Return [Table Text Block]
Average Annual Total Returns (%)1 year5 years10 years
Class
S
(a)
12.843.523.54
FTSE One-Month U.S. Treasury Bill Index4.902.761.92
Bloomberg U.S. Aggregate Bond Index5.46(0.90
)
1.49
(a)
The returns shown for periods prior to October 2, 2024 (including Since Fund Inception returns, if shown) include the returns of Class A. These returns are adjusted to reflect any higher class-related operating expenses of the newer share classes, as applicable. Please visit
columbiathreadneedleus.com/investment-products/mutual-funds/appended-performance
for more information.
No Deduction of Taxes [Text Block] Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares.
Updated Performance Information Location [Text Block] Visit
columbiathreadneedleus.com/investment-products/mutual-funds
for more recent performance information.
Net Assets $ 2,180,670,766
Holdings Count | Holding 445
Advisory Fees Paid, Amount $ 14,345,650
Investment Company, Portfolio Turnover 706.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,180,670,766
Total number of portfolio holdings
445
Management services fees
(represents 0.64% of Fund average net assets)
$
14,345,650
Portfolio turnover for the reporting period
706%
Portfolio turnover for the reporting period excluding to be announced (TBA) securities
26%
Holdings [Text Block]
Graphical Representation of Fund
 
Holdings
The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change.
Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
Derivative Exposure
Long
Credit Risk8.2
%
Interest Rate Risk110.7
%
Short
Credit Risk4.6
%
Interest Rate Risk283.6
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
Credit Quality Explanation [Text Block] Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s Ratings, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's Ratings, S&P or Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily.
[1] Based on operations from October 2, 2024 (commencement of operations) through the stated period end. Had the class been open for the entire reporting period, expenses shown in the table above would have been higher.
[2] Annualized.