Investments (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available for Sale Securities
Amortized cost	$ 55,770	$ 57,201
Gross unrealized gains	2,683	1,707
Gross unrealized losses	(324)	(960)
Fair value	58,129	57,948
U.S. government and agencies
Schedule of Available for Sale Securities
Amortized cost	3,401	3,836
Gross unrealized gains	122	90
Gross unrealized losses	0	(4)
Fair value	3,523	3,922
Municipal
Schedule of Available for Sale Securities
Amortized cost	7,286	7,032
Gross unrealized gains	543	389
Gross unrealized losses	(11)	(20)
Fair value	7,818	7,401
Corporate
Schedule of Available for Sale Securities
Amortized cost	41,134	41,674
Gross unrealized gains	1,839	1,032
Gross unrealized losses	(273)	(879)
Fair value	42,700	41,827
Foreign government
Schedule of Available for Sale Securities
Amortized cost	1,091	983
Gross unrealized gains	61	50
Gross unrealized losses	0	0
Fair value	1,152	1,033
Asset-backed securities (“ABS”)
Schedule of Available for Sale Securities
Amortized cost	1,737	2,359
Gross unrealized gains	11	11
Gross unrealized losses	(22)	(43)
Fair value	1,726	2,327
Residential mortgage-backed securities (“RMBS”)
Schedule of Available for Sale Securities
Amortized cost	748	857
Gross unrealized gains	81	100
Gross unrealized losses	(11)	(10)
Fair value	818	947
Commercial mortgage-backed securities (“CMBS”)
Schedule of Available for Sale Securities
Amortized cost	352	438
Gross unrealized gains	23	32
Gross unrealized losses	(7)	(4)
Fair value	368	466
Redeemable preferred stock
Schedule of Available for Sale Securities
Amortized cost	21	22
Gross unrealized gains	3	3
Gross unrealized losses	0	0
Fair value	$ 24	$ 25

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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