Fair Value Measurements (tables)

9 Months Ended

Sep. 30, 2013

Fair Value Measurements disclosure

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

(at September 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	$	2,109	$	2,092	$	17	$	—
Obligations of states, municipalities and political subdivisions	36,250		2		36,224		24
Debt securities issued by foreign governments	1,974		—		1,974		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,516		—		2,484		32
All other corporate bonds	19,221		—		19,024		197
Redeemable preferred stock	32		—		32		—
Total fixed maturities	62,102		2,094		59,755		253
Equity securities
Common stock	584		584		—		—
Non-redeemable preferred stock	124		24		100		—
Total equity securities	708		608		100		—
Other investments	50		18		—		32
Total	$	62,860	$	2,720	$	59,855	$	285

(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 September 30, 2013 (in millions)	FixedMaturities			OtherInvestments			Total
Balance at June 30, 2013	$	225		$	33		$	258
Total realized and unrealized investment gains (losses):
Reported in net realized investment gains (1)	1			(1		)	—
Reported in increases (decreases) in other comprehensive income	2			—			2
Purchases, sales and settlements/maturities:
Purchases	42			—			42
Sales	(1		)	—			(1		)
Settlements/maturities	(11		)	—			(11		)
Gross transfers into Level 3	2			—			2
Gross transfers out of Level 3	(7		)	—			(7		)
Balance at September 30, 2013	$	253		$	32		$	285
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.

Nine Months Ended September 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)	3			12			15
Reported in increases (decreases) in other comprehensive income	—			(1		)	(1		)
Purchases, sales and settlements/maturities:
Purchases	119			—			119
Sales	(25		)	(33		)	(58		)
Settlements/maturities	(58		)	—			(58		)
Gross transfers into Level 3	15			—			15
Gross transfers out of Level 3	(31		)	—			(31		)
Balance at September 30, 2013	$	253		$	32		$	285
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 September 30, 2013, in millions)	Carrying Value		Fair Value		Level 1		Level 2		Level 3
Financial assets:
Short-term securities	$	5,379	$	5,379	$	1,995	$	3,323	$	61
Financial liabilities:
Debt	$	6,246	$	7,239	$	—	$	7,239	$	—
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	$	—