Fair Values of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2013

Fair Value Disclosures [Abstract]

Carrying Values and Fair Values of Financial Instruments

The carrying values and fair values of financial instruments were as follows:

	March 31, 2013				December 31, 2012
	Carrying Value		Fair Value		Carrying Value		Fair Value
	(in millions)
Assets
Invested assets
Short term investments	$	1,860	$	1,860	$	2,528	$	2,528
Fixed maturities		38,216		38,216		38,076		38,076
Equity securities		1,848		1,848		1,663		1,663
Other invested assets		63		63		46		46
Liabilities
Long term debt		3,575		4,331		3,575		4,372

Fair Value of Financial Instruments Categorized Based Upon Lowest Level of Input

The fair value of financial instruments categorized based upon the lowest level of input that was significant to the fair value measurement was as follows:

	March 31, 2013
	Level 1		Level 2		Level 3		Total
	(in millions)
Assets
Short term investments	$	180	$	1,680	$	—	$	1,860
Fixed maturities
Tax exempt		—		19,704		5		19,709
Taxable
U.S. government and government agency and authority obligations		—		1,026		—		1,026
Corporate bonds		—		8,385		137		8,522
Foreign government and government agency obligations		—		6,959		—		6,959
Residential mortgage-backed securities		—		398		8		406
Commercial mortgage-backed securities		—		1,594		—		1,594
		—		18,362		145		18,507
Total fixed maturities		—		38,066		150		38,216
Equity securities		1,834		—		14		1,848
Other invested assets		—		—		63		63
	$	2,014	$	39,746	$	227	$	41,987
Liabilities
Long term debt	$	—	$	4,331	$	—	$	4,331

	December 31, 2012
	Level 1		Level 2		Level 3		Total
	(in millions)
Assets
Short term investments	$	182	$	2,346	$	—	$	2,528
Fixed maturities
Tax exempt		—		19,907		6		19,913
Taxable
U.S. government and government agency and authority obligations		—		1,039		—		1,039
Corporate bonds		—		7,779		158		7,937
Foreign government and government agency obligations		—		7,008		—		7,008
Residential mortgage-backed securities		—		446		9		455
Commercial mortgage-backed securities		—		1,724		—		1,724
		—		17,996		167		18,163
Total fixed maturities		—		37,903		173		38,076
Equity securities		1,655		—		8		1,663
Other invested assets		—		—		46		46
	$	1,837	$	40,249	$	227	$	42,313
Liabilities
Long term debt	$	—	$	4,372	$	—	$	4,372