v3.8.0.1
Closed Block (Information Regarding Policyholder Dividend Obligation) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Movement in Closed Block Dividend Obligation [Roll Forward]    
Balance, January 1 $ 4,658 $ 4,509
Impact from earnings allocable to policyholder dividend obligation 142 (48)
Change in net unrealized investment gains (losses) allocated to policyholder dividend obligation 646 197
Balance, December 31 $ 5,446 $ 4,658