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Investment Holding Level 4 Other-Than-Temporary Impairment Losses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Held-to-maturity Securities	$ 13	$ 12	$ 36	$ 16
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	14	40	44	63
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	14	40	44	63
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held	287	337	287	337	$ 293	$ 324	$ 388	$ 424
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, No Previous Impairment	4	0	25	3
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses	9	12	11	13
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	14	51	50	61
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Change in Status	0	0	0	2
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Cash Flows	5	12	23	40
Available-for-sale Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	0	21	3	38
Equity Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	1	6	5	6
Other Equity Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	$ 0	$ 1	$ 0	$ 3