Closed Block (Revenues and Expenses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Premiums	$ 405	$ 413	$ 1,202	$ 1,247
Net investment income	443	450	1,318	1,368
Net investment gains (losses)	7	0	(46)	(10)
Net derivative gains (losses)	2	(6)	12	(24)
Total revenues	857	857	2,486	2,581
Expenses
Policyholder benefits and claims	641	591	1,808	1,773
Policyholder dividends	241	235	723	732
Other expenses	29	30	88	94
Total expenses	911	856	2,619	2,599
Revenues, net of expenses before provision for income tax expense (benefit)	(54)	1	(133)	(18)
Provision for income tax expense (benefit)	(12)	0	(29)	(8)
Revenues, net of expenses and provision for income tax expense (benefit)	$ (42)	$ 1	$ (104)	$ (10)