v3.8.0.1
Commitments and Guarantees, Contingent Liabilities and Litigation and Regulatory Matters (Commitments and Guarantees) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Other assets:    
Premium tax offset for future undiscounted assessments $ 64 $ 78
Premium tax offset currently available for paid assessments 6 6
Total 70 84
Other liabilities:    
Insolvency assessments 39 52
Other Guarantees    
Commitments and Guarantees and Contingent Liabilities [Line Items]    
Other guarantees where amount can be determined 31 58
Accrued liability for other guarantees and indemnifications 0 3
Commitments | Serviced Mortgages Loans    
Commitments and Guarantees and Contingent Liabilities [Line Items]    
Total outstanding mortgage loan commitments 2,772 1,984
Portion of commitment where prearrangement to sell to investor exists 435 454
Expected to be funded from the GA and other operations outside the SA    
Commitments and Guarantees and Contingent Liabilities [Line Items]    
Commitments to Purchase Investment (excluding Commercial Mortgage Loans) 6,319 7,232
Expected to be funded from separate accounts    
Commitments and Guarantees and Contingent Liabilities [Line Items]    
Commitments to Purchase Investment (excluding Commercial Mortgage Loans) 141 470
Indemnification | Securities Lending Transactions    
Commitments and Guarantees and Contingent Liabilities [Line Items]    
Indemnification provided to certain securities lending clients 4,619 5,352
Fair value of related collateral associated with above indemnifications 4,722 5,465
Accrued liability for other guarantees and indemnifications 0 0
Indemnification | Serviced Mortgages Loans    
Commitments and Guarantees and Contingent Liabilities [Line Items]    
Maximum exposure under indemnification agreements for mortgage loans serviced by the Company 1,609 1,371
First-loss exposure portion of above 483 416
Accrued liability for other guarantees and indemnifications 14 13
Guarantee of Asset Values    
Commitments and Guarantees and Contingent Liabilities [Line Items]    
Guaranteed value of third parties’ assets 77,290 77,197
Fair value of collateral supporting these assets 77,651 77,760
Asset (liability) associated with guarantee, carried at fair value $ (1) $ 5