v3.25.2
Shareholder Report
 6 Months Ended
Jun. 30, 2025
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name Capital Group Completion Fund Series
Entity Central Index Key 0002020645
Entity Investment Company Type N-1A
Document Period End Date Jun. 30, 2025
Capital Group Core Bond Completion Fund - CBCFX  
Shareholder Report [Line Items]  
Fund Name Capital Group Core Bond Completion Fund
Class Name Capital Group Core Bond Completion Fund
Trading Symbol CBCFX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Capital Group Core Bond Completion Fund (the "fund") for the period from September 13, 2024, commencement of operations, to June 30, 2025.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the fund at
capitalgroup.com/CGCBCF-M
. You can also request this information by contacting us at
(800) 421-4225.
Additional Information Phone Number (800) 421-4225
Additional Information Website capitalgroup.com/CGCBCF-M
Expenses [Text Block]
What were the fund costs for the last six months?
(based on a hypothetical $10,000 investment)
Fund
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
CBCFX
$
0
*
0.00
%
†
*
Based on operations
for
the
period from
September
13, 2024 to
June
30, 2025. Expenses for the full 6
mo
nths would be higher.
†
Annualized.
Expenses Paid, Amount $ 0 [1]
Expense Ratio, Percent 0.00% [2]
Net Assets $ 30,000,000
Holdings Count | Holding 272
Investment Company, Portfolio Turnover 204.00%
Additional Fund Statistics [Text Block]
Key fund statistics
Fund net assets (in millions)
$
30
Total number of portfolio holdings272
Portfolio turnover rate including
mortgage dollar roll transactions		204
%
Portfolio turnover rate excluding mortgage dollar roll transactions17
%
Holdings [Text Block]
Portfolio holdings by asset type
 (percent of net assets)
Graphical Representation - Allocation 1 Chart
*Includes derivatives.
[1] Based on operations for the period from September 13, 2024 to June 30, 2025. Expenses for the full 6 months would be higher.
[2] Annualized.