Acquisitions and Sale of Businesses - Impact of the sale of subsidiaries sold (Details) - USD ($) $ in Millions			3 Months Ended			12 Months Ended
		Dec. 24, 2015	Jun. 30, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Liabilities of businesses sold:
Realized gains (losses) on subsidiaries						$ 2	$ (161)	$ 0
Run-off long-term care insurance business
Sale of Businesses
Net sale proceeds	[1]	$ 13
Assets of businesses sold:
Cash and investments		1,334
Recoverables from reinsurers		630
Deferred policy acquisition costs		16
Other receivables		16
Other assets		(4)
Goodwill		2
Total assets		1,994
Liabilities of businesses sold:
Annuity benefits accumulated		261
Life, accident and health reserves		1,525
Other liabilities		7
Total liabilities		1,793
Reclassify net unrealized gain on marketable securities		22
Net assets of businesses sold		179
Realized gains (losses) on subsidiaries		(166)	$ 2	$ (4)	$ (162)		$ (166)
Tax benefit		58
Loss on subsidiaries, net of tax		$ (108)			$ (105)

[1] Includes the fair value of the potential additional consideration and capital maintenance agreement and is shown net of estimated expenses.