v3.8.0.1
Variable Interest Entities (Assets and Liabilities of Consolidated VIEs) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Variable Interest Entity [Line Items]    
Total liabilities of consolidated VIEs [1] $ 1,518 $ 2,150
Consolidated VIEs for Which the Company is the Investment Manager    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs [2] 4,421 4,924
Total liabilities of consolidated VIEs $ 1,951 $ 2,761
VIEs Liabilities, maturities obligations (greater than) 5 years 5 years
Consolidated VIEs for Which the Company is the Investment Manager | Trading account assets supporting insurance liabilities    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs $ 0 $ 0
Consolidated VIEs for Which the Company is the Investment Manager | Other trading account assets    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 1,652 2,140
Consolidated VIEs for Which the Company is the Investment Manager | Commercial mortgage and other loans    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 617 503
Consolidated VIEs for Which the Company is the Investment Manager | Other long-term investments    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 1,389 1,083
Consolidated VIEs for Which the Company is the Investment Manager | Cash and cash equivalents    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 164 618
Consolidated VIEs for Which the Company is the Investment Manager | Accrued investment income    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 7 10
Consolidated VIEs for Which the Company is the Investment Manager | Other assets    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 440 424
Consolidated VIEs for Which the Company is the Investment Manager | Notes issued by consolidated VIEs    
Variable Interest Entity [Line Items]    
Total liabilities of consolidated VIEs [3] 1,518 2,150
Consolidated VIEs for Which the Company is the Investment Manager | Other liabilities    
Variable Interest Entity [Line Items]    
Total liabilities of consolidated VIEs 433 611
Other Consolidated VIEs    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 1,345 1,181
Total liabilities of consolidated VIEs 0 7
Other Consolidated VIEs | Trading account assets supporting insurance liabilities    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 9 9
Other Consolidated VIEs | Other trading account assets    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 0 0
Other Consolidated VIEs | Commercial mortgage and other loans    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 0 0
Other Consolidated VIEs | Other long-term investments    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 97 114
Other Consolidated VIEs | Cash and cash equivalents    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 0 1
Other Consolidated VIEs | Accrued investment income    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 4 4
Other Consolidated VIEs | Other assets    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 150 1
Other Consolidated VIEs | Notes issued by consolidated VIEs    
Variable Interest Entity [Line Items]    
Total liabilities of consolidated VIEs 0 0
Other Consolidated VIEs | Other liabilities    
Variable Interest Entity [Line Items]    
Total liabilities of consolidated VIEs 0 7
Available-for-sale | Consolidated VIEs for Which the Company is the Investment Manager | Fixed maturities    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 69 65
Available-for-sale | Other Consolidated VIEs | Fixed maturities    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 275 269
Held-to-maturity | Consolidated VIEs for Which the Company is the Investment Manager | Fixed maturities    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 83 81
Held-to-maturity | Other Consolidated VIEs | Fixed maturities    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs 810 783
ASU 2015-02, Wholly-owned by consolidated subsidiaries | Consolidated VIEs for Which the Company is the Investment Manager    
Variable Interest Entity [Line Items]    
Total assets of consolidated VIEs $ 1,716 $ 1,386
[1] See Note 5 for details of balances associated with variable interest entities.
[2] Total assets of consolidated VIEs reflect $1,716 million and $1,386 million as of December 31, 2017 and 2016, respectively, related to VIEs whose beneficial interests are wholly-owned by consolidated subsidiaries.
[3] Recourse is limited to the assets of the respective VIE and does not extend to the general credit of the Company. As of December 31, 2017 and December 31, 2016, the maturities of these obligations were greater than five years.