Business Dispositions and Discontinued Operations - Cash Flows from Discontinued Operations (Details) - Run-Off Life and Annuity Business - Discontinued Operations, Held-for-sale - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash provided by operating activities from discontinued operations	$ 267	$ 342
Net cash provided by investing activities from discontinued operations	(187)	(467)
Net cash used in financing activities from discontinued operations	(340)	105
Cash paid for interest	$ 2	2
Return to capital to parent		$ 0