You can find additional information about the Fund at https://connect.rightprospectus.com/russellinvestments?Site=RIF. You can also request this information by contacting us at 1-800-787-7354 or by sending an e-mail to: service@russellinvestments.com.

Additional Information Phone Number

1-800-787-7354

Additional Information Email

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Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Fund Name	Costs of $10,000 Investment	Costs Paid as % of $10,000 Investment
U.S. Strategic Equity Fund	$46	0.88%

Expenses Paid, Amount

$ 46

Expense Ratio, Percent

0.88%

AssetsNet

$ 660,802,000

Holdings Count | Holding

515

Advisory Fees Paid, Amount

$ 2,194,000

InvestmentCompanyPortfolioTurnover

28.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Net Assets (thousands)$660,802
Total Number of Portfolio Holdings 515
Total Advisory Fees Paid (thousands) $2,194
Portfolio Turnover Rate28%

Holdings [Text Block]

Asset Type Exposure

Table Summary
Value	Value
Other	0.1%
Securities Sold Short	(6.1)%
Short-Term Investments	2.8%
Common Stocks	103.2%

Sector Exposure - Common Stocks

(% of Net Assets)

Table Summary
Value	Value
Technology	44.4%
Financial Services	13.8%
Consumer Discretionary	12.9%
Health Care	10.5%
Producer Durables	8.4%
Materials and Processing	3.8%
Energy	3.4%
Utilities	3.1%
Consumer Staples	2.9%
Other	(3.2)%

C000018546

Shareholder Report [Line Items]

Fund Name

U.S. Small Cap Equity Fund

Trading Symbol

RIFBX

Annual or Semi-Annual Statement [Text Block]

Semi-Annual Shareholder Report

Additional Information [Text Block]

Additional Information Phone Number

1-800-787-7354

Additional Information Email

Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Fund Name	Costs of $10,000 Investment	Costs Paid as % of $10,000 Investment
U.S. Small Cap Equity Fund	$60	1.07%

Expenses Paid, Amount

$ 60

Expense Ratio, Percent

1.07%

AssetsNet

$ 244,880,000

Holdings Count | Holding

1,182

Advisory Fees Paid, Amount

$ 941,000

InvestmentCompanyPortfolioTurnover

46.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Net Assets (thousands)$244,880
Total Number of Portfolio Holdings 1,182
Total Advisory Fees Paid (thousands) $941
Portfolio Turnover Rate46%

Holdings [Text Block]

Asset Type Exposure

Table Summary
Value	Value
Other	0.2%
Securities Sold Short	(3.4)%
Short-Term Investments	5.4%
Common Stocks	97.8%

Sector Exposure - Common Stocks

(% of Net Assets)

Table Summary
Value	Value
Producer Durables	19.3%
Financial Services	19.1%
Health Care	18.2%
Technology	13.7%
Consumer Discretionary	9.6%
Materials and Processing	8.1%
Energy	4.9%
Utilities	2.7%
Consumer Staples	2.2%
Other	2.2%

C000018547

Shareholder Report [Line Items]

Fund Name

International Developed Markets Fund

Trading Symbol

RIFCX

Annual or Semi-Annual Statement [Text Block]

Semi-Annual Shareholder Report

Additional Information [Text Block]

Additional Information Phone Number

1-800-787-7354

Additional Information Email

Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Fund Name	Costs of $10,000 Investment	Costs Paid as % of $10,000 Investment
International Developed Markets Fund	$50	0.97%

Expenses Paid, Amount

$ 50

Expense Ratio, Percent

0.97%

AssetsNet

$ 399,390,000

Holdings Count | Holding

574

Advisory Fees Paid, Amount

$ 1,634,000

InvestmentCompanyPortfolioTurnover

33.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Net Assets (thousands)$399,390
Total Number of Portfolio Holdings 574
Total Advisory Fees Paid (thousands) $1,634
Portfolio Turnover Rate33%

Holdings [Text Block]

Asset Type Exposure

Table Summary
Value	Value
Other	2.0%
Preferred Stocks	0.7%
Short-Term Investments	3.0%
Common Stocks	94.3%

Country Exposure - Common Stocks

(% of Net Assets)

Table Summary
Value	Value
Japan	16.9%
United Kingdom	10.7%
France	9.1%
Germany	6.6%
United States	6.2%
Netherlands	5.4%
Canada	5.1%
Italy	3.9%
Switzerland	3.9%
Taiwan	3.5%
Other Common Stocks	23.0%
Other	5.7%

C000018549

Shareholder Report [Line Items]

Fund Name

Strategic Bond Fund

Trading Symbol

RIFDX

Annual or Semi-Annual Statement [Text Block]

Semi-Annual Shareholder Report

Additional Information [Text Block]

Additional Information Phone Number

1-800-787-7354

Additional Information Email

Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Fund Name	Costs of $10,000 Investment	Costs Paid as % of $10,000 Investment
Strategic Bond Fund	$32	0.64%

Expenses Paid, Amount

$ 32

Expense Ratio, Percent

0.64%

AssetsNet

$ 852,980,000

Holdings Count | Holding

988

Advisory Fees Paid, Amount

$ 2,304,000

InvestmentCompanyPortfolioTurnover

30.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Net Assets (thousands)$852,980
Total Number of Portfolio Holdings 988
Total Advisory Fees Paid (thousands) $2,304
Portfolio Turnover Rate30%

Holdings [Text Block]

Asset Type Exposure

Table Summary
Value	Value
Other	0.7%
Investments in Affiliated Funds	1.5%
Short-Term Investments	14.4%
Long-Term Fixed Income Investments	83.4%

Long-Term Fixed Income Exposure

(% of Net Assets)

Table Summary
Value	Value
Corporate Bonds and Notes	26.2%
Mortgage-Backed Securities	23.6%
International Debt	12.3%
United States Government Treasuries	10.4%
Asset-Backed Securities	5.9%
Non-US Bonds	4.9%
United States Government Agencies	0.1%
Other	16.6%

C000018548

Shareholder Report [Line Items]

Fund Name

Global Real Estate Securities Fund

Trading Symbol

RIFSX

Annual or Semi-Annual Statement [Text Block]

Semi-Annual Shareholder Report

Additional Information [Text Block]

Additional Information Phone Number

1-800-787-7354

Additional Information Email

Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment)

Table Summary
Fund Name	Costs of $10,000 Investment	Costs Paid as % of $10,000 Investment
Global Real Estate Securities Fund	$47	0.90%

Expenses Paid, Amount

$ 47

Expense Ratio, Percent

0.90%

AssetsNet

$ 1,033,826,000

Holdings Count | Holding

142

Advisory Fees Paid, Amount

$ 4,054,000

InvestmentCompanyPortfolioTurnover

43.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Net Assets (thousands)$1,033,826
Total Number of Portfolio Holdings 142
Total Advisory Fees Paid (thousands) $4,054
Portfolio Turnover Rate43%

Holdings [Text Block]

Asset Type Exposure

Table Summary
Value	Value
Other	0.6%
Short-Term Investments	3.4%
Common Stocks	96.0%

Country Exposure - Common Stocks

(% of Net Assets)

Table Summary
Value	Value
United States	63.1%
Japan	7.6%
Australia	5.8%
United Kingdom	4.0%
Singapore	3.0%
Hong Kong	2.7%
France	2.3%
Germany	1.9%
Belgium	1.4%
Canada	1.4%
Other Common Stocks	2.8%
Other	4.0%