Invested Assets (Tables)

3 Months Ended

Mar. 31, 2013

Text Block [Abstract]

Amortized Cost and Fair Value of Fixed Maturities and Equity Securities

(a) The amortized cost and fair value of fixed maturities and equity securities were as follows:

	March 31, 2013
	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
	(in millions)
Fixed maturities
Tax exempt	$	18,333	$	1,406	$	30	$	19,709
Taxable
U.S. government and government agency and authority obligations		961		65		—		1,026
Corporate bonds		7,949		579		6		8,522
Foreign government and government agency obligations		6,592		369		2		6,959
Residential mortgage-backed securities		374		33		1		406
Commercial mortgage-backed securities		1,525		70		1		1,594
		17,401		1,116		10		18,507
Total fixed maturities	$	35,734	$	2,522	$	40	$	38,216
Equity securities	$	1,227	$	635	$	14	$	1,848

	December 31, 2012
	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
	(in millions)
Fixed maturities
Tax exempt	$	18,410	$	1,522	$	19	$	19,913
Taxable
U.S. government and government agency and authority obligations		973		66		—		1,039
Corporate bonds		7,331		609		3		7,937
Foreign government and government agency obligations		6,614		395		1		7,008
Residential mortgage-backed securities		421		36		2		455
Commercial mortgage-backed securities		1,649		76		1		1,724
		16,988		1,182		7		18,163
Total fixed maturities	$	35,398	$	2,704	$	26	$	38,076
Equity securities	$	1,244	$	453	$	34	$	1,663

Fair Value and Amortized Cost of Fixed Maturities by Contractual Maturity

The fair value and amortized cost of fixed maturities at March 31, 2013 by contractual maturity were as follows:

	Fair Value		Amortized Cost
	(in millions)
Due in one year or less	$	2,174	$	2,148
Due after one year through five years		14,525		13,758
Due after five years through ten years		11,494		10,458
Due after ten years		8,023		7,471
		36,216		33,835
Residential mortgage-backed securities		406		374
Commercial mortgage-backed securities		1,594		1,525
	$	38,216	$	35,734

Components of Unrealized Appreciation or Depreciation of Investments

(b) The components of unrealized appreciation or depreciation, including unrealized other-than-temporary impairment losses, of investments carried at fair value were as follows:

	March 31 2013		December 31 2012
	(in millions)
Fixed maturities
Gross unrealized appreciation	$	2,522	$	2,704
Gross unrealized depreciation		40		26
		2,482		2,678
Equity securities
Gross unrealized appreciation		635		453
Gross unrealized depreciation		14		34
		621		419
		3,103		3,097
Deferred income tax liability		1,086		1,084
	$	2,017	$	2,013

Fair Value and Gross Unrealized Depreciation of Investments in Unrealized Loss Position

The following table summarizes, for all investment securities in an unrealized loss position at March 31, 2013, the aggregate fair value and gross unrealized depreciation, including unrealized other-than-temporary impairment losses, by investment category and length of time that individual securities have continuously been in an unrealized loss position.

	Less Than 12 Months				12 Months or More				Total
	Fair Value		Gross Unrealized Depreciation		Fair Value		Gross Unrealized Depreciation		Fair Value		Gross Unrealized Depreciation
	(in millions)
Fixed maturities
Tax exempt	$	1,065	$	19	$	114	$	11	$	1,179	$	30
Taxable
U.S. government and government agency and authority obligations		18		—		20		—		38		—
Corporate bonds		625		5		14		1		639		6
Foreign government and government agency obligations		289		2		—		—		289		2
Residential mortgage-backed securities		—		—		19		1		19		1
Commercial mortgage-backed securities		128		1		—		—		128		1
		1,060		8		53		2		1,113		10
Total fixed maturities		2,125		27		167		13		2,292		40
Equity securities		91		9		34		5		125		14
	$	2,216	$	36	$	201	$	18	$	2,417	$	54

The following table summarizes, for all investment securities in an unrealized loss position at December 31, 2012, the aggregate fair value and gross unrealized depreciation, including unrealized other-than-temporary impairment losses, by investment category and length of time that individual securities have continuously been in an unrealized loss position.

	Less Than 12 Months				12 Months or More				Total
	Fair Value		Gross Unrealized Depreciation		Fair Value		Gross Unrealized Depreciation		Fair Value		Gross Unrealized Depreciation
	(in millions)
Fixed maturities
Tax exempt	$	344	$	6	$	104	$	13	$	448	$	19
Taxable
U.S. government and government agency and authority obligations		28		—		20		—		48		—
Corporate bonds		289		2		14		1		303		3
Foreign government and government agency obligations		429		1		13		—		442		1
Residential mortgage-backed securities		1		—		19		2		20		2
Commercial mortgage-backed securities		105		1		3		—		108		1
		852		4		69		3		921		7
Total fixed maturities		1,196		10		173		16		1,369		26
Equity securities		182		21		63		13		245		34
	$	1,378	$	31	$	236	$	29	$	1,614	$	60

Change in Unrealized Appreciation or Depreciation of Investments Carried at Fair Value

The change in unrealized appreciation or depreciation of investments carried at fair value, including the change in unrealized other-than-temporary impairment losses, was as follows:

	Three Months Ended March 31
	2013			2012
	(in millions)
Change in unrealized appreciation of fixed maturities	$	(196	)	$	(17	)
Change in unrealized appreciation of equity securities		202			102
		6			85
Deferred income tax		2			30
	$	4		$	55

Realized Investment Gains and Losses

(c) Realized investment gains and losses were as follows:

	Three Months Ended March 31
	2013			2012
	(in millions)
Fixed maturities
Gross realized gains	$	13		$	38
Gross realized losses		(2	)		(3	)
Other-than-temporary impairment losses		—			(1	)
		11			34
Equity securities
Gross realized gains		55			19
Other-than-temporary impairment losses		(2	)		(5	)
		53			14
Other invested assets		74			8
	$	138		$	56