Fair Value of Assets and Liabilities - Change In Unrealized Gains and Losses included in Net Income for Level 3 (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 assets	$ 4	$ 6	$ 6	$ 7
Total recurring Level 3 liabilities	(11)	2	(36)	25
Total	(7)	6	(19)	30
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	(11)	2	(36)	25
Equity securities
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 assets	5	6	7	7
Free-standing derivatives, net
Gains (losses) included in net income for Level 3 assets and liabilities:
Total recurring Level 3 assets	(1)	0	(1)	0
Realized capital gains and losses
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets and liabilities still held at the balance sheet date	2	6	4	7
Interest credited to contractholder funds
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets and liabilities still held at the balance sheet date	(6)	1	(39)	20
Contract benefits
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 assets and liabilities still held at the balance sheet date	(5)	1	3	5
Total
Gains (losses) included in net income for Level 3 assets and liabilities:
Total	$ (7)	$ 8	$ (30)	$ 32