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		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Benefits, losses and expenses
Income from discontinued operations, net of tax	$ 5	$ 89	$ 322	$ 276
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Revenues
Earned premiums	0	27	39	97
Fee income and other	0	217	382	665
Net investment income	0	326	519	964
Net realized capital gains (losses)	4	(29)	(68)	(53)
Total revenues	4	541	872	1,673
Benefits, losses and expenses
Benefits, losses and loss adjustment expenses	0	356	535	1,036
Amortization of DAC	0	15	58	58
Insurance operating costs and other expenses [1]	(5)	93	157	275
Total benefits, losses and expenses	(5)	464	750	1,369
Income before income taxes	9	77	122	304
Income tax expense (benefit)	(7)	(12)	2	28
Income from operations of discontinued operations, net of tax	16	89	120	276
Net realized capital gain (loss) on disposal, net of tax	(11)	0	202	0
Income from discontinued operations, net of tax	$ 5	$ 89	$ 322	$ 276