Quarterly Operating Results (Unaudited) - Impact of fair value accounting on annuities (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Impact of Unlocking, Changes in the Fair Value of Derivatives, and Changes in the Stock Market and Interest Rates on the Accounting for FIAs	$ 24	$ (27)	$ (33)	$ (11)	$ (66)	$ 17	$ (14)	$ 15	$ (47)	$ (48)