Closed Block (Revenues and Expenses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues
Premiums	$ 413	$ 436	$ 1,247	$ 1,297
Net investment income	450	486	1,368	1,435
Net investment gains (losses)	0	(3)	(10)	(19)
Net derivative gains (losses)	(6)	4	(24)	(3)
Total revenues	857	923	2,581	2,710
Expenses
Policyholder benefits and claims	591	619	1,773	1,861
Policyholder dividends	235	232	732	723
Other expenses	30	33	94	100
Total expenses	856	884	2,599	2,684
Revenues, net of expenses before provision for income tax expense (benefit)	1	39	(18)	26
Provision for income tax expense (benefit)	0	13	(8)	8
Revenues, net of expenses and provision for income tax expense (benefit)	$ 1	$ 26	$ (10)	$ 18