v3.8.0.1
Variable Interest Entities (Narrative) (Details) - USD ($)
Dec. 31, 2017
Dec. 31, 2016
Variable Interest Entity [Line Items]    
Other long-term investments [1] $ 12,308,000,000 $ 11,283,000,000
Other Consolidated VIEs    
Variable Interest Entity [Line Items]    
Liabilities held within unconsolidated VIEs 0  
Other Consolidated VIEs | Fixed maturities, AFS, Other trading account assets, at FV, and Other long-term investments    
Variable Interest Entity [Line Items]    
Maximum exposure to loss resulting from investment in unconsolidated VIEs 1,013,000,000 515,000,000
VIEs and Non-VIEs | Joint ventures and limited partnerships    
Variable Interest Entity [Line Items]    
Other long-term investments $ 8,720,000,000 $ 8,010,000,000
[1] See Note 5 for details of balances associated with variable interest entities.