Fair Value of Assets and Liabilities - Gains and Losses included in Net Income for Level 3 (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 assets	$ 3	$ 3	$ 9	$ 10
Total recurring Level 3 liabilities	(12)	(6)	(48)	19
Total included in net income	(9)	(3)	(39)	29
Contractholder funds: Derivatives embedded in life and annuity contracts
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 liabilities	(12)	(6)	(48)	19
Equity securities
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 assets	3	3	10	10
Free-standing derivatives, net
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 assets	0	0	(1)	0
Net investment income
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 assets	1	0	3	0
Realized capital gains and losses
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 assets	2	3	6	10
Contract benefits
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 assets	(1)	2	2	7
Interest credited to contractholder funds
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 assets	$ (11)	$ (8)	$ (50)	$ 12