Investments (AFS securities)(Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	$ 73,532	$ 69,796
Gross unrealized gains	9,884	7,585
Gross unrealized losses	(320)	(906)
Gross unrealized OTTI	(195)	(203)
Fair Value	82,901	76,272
Corporate bonds [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	60,124	53,661
Gross unrealized gains	8,219	6,185
Gross unrealized losses	(219)	(517)
Gross unrealized OTTI	(108)	(68)
Fair Value	68,016	59,261
U.S. government bonds [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	383	439
Gross unrealized gains	59	55
Gross unrealized losses	0	0
Gross unrealized OTTI	0	0
Fair Value	442	494
Foreign government bonds [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	562	668
Gross unrealized gains	92	65
Gross unrealized losses	0	0
Gross unrealized OTTI	0	0
Fair Value	654	733
RMBS [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	5,763	7,690
Gross unrealized gains	471	548
Gross unrealized losses	(3)	(73)
Gross unrealized OTTI	(60)	(126)
Fair Value	6,171	8,039
CMBS [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	970	1,642
Gross unrealized gains	68	73
Gross unrealized losses	(16)	(106)
Gross unrealized OTTI	(19)	(9)
Fair Value	1,003	1,600
CDOs [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	189	121
Gross unrealized gains	2	0
Gross unrealized losses	(3)	(19)
Gross unrealized OTTI	(8)	0
Fair Value	180	102
State and municipal bonds [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	3,546	3,490
Gross unrealized gains	814	566
Gross unrealized losses	(7)	(9)
Gross unrealized OTTI	0	0
Fair Value	4,353	4,047
Hybrid and redeemable preferred securities [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	1,181	1,277
Gross unrealized gains	106	50
Gross unrealized losses	(70)	(170)
Gross unrealized OTTI	0	0
Fair Value	1,217	1,157
Variable Interest Entities Fixed Maturity Securities [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	677	673
Gross unrealized gains	31	27
Gross unrealized losses	0	0
Gross unrealized OTTI	0	0
Fair Value	708	700
Fixed maturity securities [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	73,395	69,661
Gross unrealized gains	9,862	7,569
Gross unrealized losses	(318)	(894)
Gross unrealized OTTI	(195)	(203)
Fair Value	82,744	76,133
Equity securities [Member]
Amortized Cost Gross Unrealized Gains Losses Otti And Fair Value Of Afs Securities [Abstract]
Amortized cost	137	135
Gross unrealized gains	22	16
Gross unrealized losses	(2)	(12)
Gross unrealized OTTI	0	0
Fair Value	$ 157	$ 139

This item represents the cost of debt and equity 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.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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