Fair Value Measurements (tables)

6 Months Ended

Jun. 30, 2013

Fair Value Measurements disclosure

Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured [Table Text Block]

(at June 30, 2013, in millions)	Total		Level 1		Level 2		Level 3
Invested assets:
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,103	$	2,086	$	17	$	—
Obligations of states, municipalities and political subdivisions	37,068		—		37,042		26
Debt securities issued by foreign governments	2,079		—		2,079		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,595		—		2,590		5
All other corporate bonds	18,966		—		18,772		194
Redeemable preferred stock	32		—		32		—
Total fixed maturities	62,843		2,086		60,532		225
Equity securities
Common stock	577		577		—		—
Non-redeemable preferred stock	124		32		92		—
Total equity securities	701		609		92		—
Other investments	50		17		—		33
Total	$	63,594	$	2,712	$	60,624	$	258

(at December 31, 2012, in millions)	Total		Level 1		Level 2		Level 3
Invested assets:
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,222	$	2,205	$	17	$	—
Obligations of states, municipalities and political subdivisions	38,681		—		38,653		28
Debt securities issued by foreign governments	2,257		—		2,257		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,997		—		2,992		5
All other corporate bonds	19,203		—		19,006		197
Redeemable preferred stock	33		32		1		—
Total fixed maturities	65,393		2,237		62,926		230
Equity securities
Common stock	510		510		—		—
Non-redeemable preferred stock	135		92		43		—
Total equity securities	645		602		43		—
Other investments	100		46		—		54
Total	$	66,138	$	2,885	$	62,969	$	284

Changes in the Level 3 fair value category [Table Text Block]

Three Months Ended June 30, 2013 (in millions)	FixedMaturities			OtherInvestments			Total
Balance at March 31, 2013	$	254		$	49		$	303
Total realized and unrealized investment gains (losses):
Reported in net realized investment gains (1)	1			13			14
Reported in increases (decreases) in other comprehensive income	(3		)	(12		)	(15		)
Purchases, sales and settlements/maturities:
Purchases	35			—			35
Sales	(24		)	(17		)	(41		)
Settlements/maturities	(27		)	—			(27		)
Gross transfers into Level 3	13			—			13
Gross transfers out of Level 3	(24		)	—			(24		)
Balance at June 30, 2013	$	225		$	33		$	258
Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date	$	—		$	—		$	—

(1) Includes impairments on investments held at the end of the period as well as amortization on fixed maturities.

Six Months Ended June 30, 2013 (in millions)	FixedMaturities			OtherInvestments			Total
Balance at December 31, 2012	$	230		$	54		$	284
Total realized and unrealized investment gains (losses):
Reported in net realized investment gains (1)	2			13			15
Reported in increases (decreases) in other comprehensive income	(2		)	(1		)	(3		)
Purchases, sales and settlements/maturities:
Purchases	77			—			77
Sales	(24		)	(33		)	(57		)
Settlements/maturities	(47		)	—			(47		)
Gross transfers into Level 3	13			—			13
Gross transfers out of Level 3	(24		)	—			(24		)
Balance at June 30, 2013	$	225		$	33		$	258
Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date	$	—		$	—		$	—

(1)   Includes impairments on investments held at the end of the period as well as amortization on fixed maturities.

Twelve Months Ended December 31, 2012 (in millions)	FixedMaturities			OtherInvestments		Total
Balance at December 31, 2011	$	250		$	44	$	294
Total realized and unrealized investment gains (losses):
Reported in net realized investment gains (1)	4			5		9
Reported in increases (decreases) in other comprehensive income	5			2		7
Purchases, sales and settlements/maturities:
Purchases	79			3		82
Sales	—			—		—
Settlements/maturities	(94		)	—		(94		)
Gross transfers into Level 3	10			—		10
Gross transfers out of Level 3	(24		)	—		(24		)
Balance at December 31, 2012	$	230		$	54	$	284
Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date	$	—		$	—	$	—

(1)     Includes impairments on investments held at the end of the period as well as amortization on fixed maturities.

Carrying value and fair value of financial instruments disclosed, but not carried, at fair value and the level within the fair value hierarchy at which such financial instruments are measured on a recurring basis [Table Text Block]

(at June 30, 2013, in millions)	Carrying Value		Fair Value		Level 1		Level 2		Level 3
Financial assets:
Short-term securities	$	3,394	$	3,394	$	1,343	$	1,990	$	61
Financial liabilities:
Debt	$	5,752	$	6,724	$	—	$	6,724	$	—
Commercial paper	$	100	$	100	$	—	$	100	$	—

(at December 31, 2012, in millions)	Carrying Value		Fair Value		Level 1		Level 2		Level 3
Financial assets:
Short-term securities	$	3,483	$	3,483	$	1,448	$	1,957	$	78
Financial liabilities:
Debt	$	6,250	$	7,715	$	—	$	7,715	$	—
Commercial paper	$	100	$	100	$	—	$	100	$	—