Closed Block (Revenues and Expenses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues
Premiums	$ 387	$ 402
Net investment income	444	466
Net investment gains (losses)	(29)	(8)
Net derivative gains (losses)	(3)	(8)
Total revenues	799	852
Expenses
Policyholder benefits and claims	571	568
Policyholder dividends	244	250
Other expenses	29	32
Total expenses	844	850
Revenues, net of expenses before provision for income tax expense (benefit)	(45)	2
Provision for income tax expense (benefit)	(10)	0
Revenues, net of expenses and provision for income tax expense (benefit)	$ (35)	$ 2