Fair Value of Assets and Liabilities - Change in unrealized gains and losses included in net income for level 3 assets and liabilities (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:
Recurring Level 3 assets	$ 11	$ 8	$ 24	$ 23
Gains (losses) for Level 3 liabilities still held at the balance sheet date, included in earnings	(14)	(7)	(54)	17
Gains (losses) for Level 3 assets and liabilities still held at the balance sheet date, included in earnings	(3)	1	(30)	40
Contractholder funds: Derivatives embedded in life and annuity contracts
Gains (losses) included in net income for Level 3 assets and liabilities:
Gains (losses) for Level 3 liabilities still held at the balance sheet date, included in earnings	(14)	(7)	(54)	17
Equity securities
Gains (losses) included in net income for Level 3 assets and liabilities:
Recurring Level 3 assets	11	8	25	23
Free-standing derivatives, net
Gains (losses) included in net income for Level 3 assets and liabilities:
Recurring Level 3 assets	0	0	(1)	0
Net Investment Income
Gains (losses) included in net income for Level 3 assets and liabilities:
Recurring Level 3 assets	5	0	10	0
Realized capital gains (losses)
Gains (losses) included in net income for Level 3 assets and liabilities:
Recurring Level 3 assets	6	8	14	23
Life contract benefits
Gains (losses) included in net income for Level 3 assets and liabilities:
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:
Recurring Level 3 assets	$ (13)	$ (9)	$ (56)	$ 10