Business Dispositions and Discontinued Operations - Reconciliation of the Major Line Items Constituting Pretax Profit (Loss) of Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Benefits, losses and expenses
Income (Loss) from Discontinued Operations, Net of Tax	$ 148	$ 112	$ 317	$ 187
Run-Off Life and Annuity Business | Discontinued Operations, Held-for-sale
Revenues
Earned premiums	12	35	39	70
Fee income and other	150	226	382	448
Net investment income	207	320	519	639
Net realized capital losses	(93)	21	(72)	(25)
Total revenues	276	602	868	1,132
Benefits, losses and expenses
Benefits, losses and loss adjustment expenses	207	346	535	679
Amortization of DAC	17	24	58	43
Insurance operating costs and other expenses	61	89	162	183
Total benefits, losses and expenses	285	459	755	905
Income before income taxes	(9)	143	113	227
Income tax expense	(6)	30	9	41
Income from operations of discontinued operations, net of tax	(3)	113	104	186
Discontinued Operation, Amount of Adjustment to Prior Period Gain (Loss) on Disposal, Net of Tax	151	0	213	0
Income (Loss) from Discontinued Operations, Net of Tax	$ 148	$ 113	$ 317	$ 186