Closed Block (Revenues and Expenses) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues
Premiums	$ 432	$ 444	$ 834	$ 861
Net investment income	452	469	918	949
Net investment gains (losses)	(2)	12	(10)	(16)
Net derivative gains (losses)	(10)	4	(18)	(7)
Total revenues	872	929	1,724	1,787
Expenses
Policyholder benefits and claims	614	632	1,182	1,242
Policyholder dividends	247	246	497	491
Other expenses	32	35	64	67
Total expenses	893	913	1,743	1,800
Revenues, net of expenses before provision for income tax expense (benefit)	(21)	16	(19)	(13)
Provision for income tax expense (benefit)	(8)	6	(8)	(5)
Revenues, net of expenses and provision for income tax expense (benefit)	$ (13)	$ 10	$ (11)	$ (8)