Fair Value Measurements (tables)

3 Months Ended

Mar. 31, 2016

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 March 31, 2016, 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	$	2,154	$	2,154	$	—	$	—
Obligations of states, municipalities and political subdivisions	32,322		—		32,309		13
Debt securities issued by foreign governments	1,846		—		1,846		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,929		—		1,927		2
All other corporate bonds	23,620		—		23,433		187
Redeemable preferred stock	114		3		104		7
Total fixed maturities	61,985		2,157		59,619		209
Equity securities
Public common stock	549		549		—		—
Non-redeemable preferred stock	161		64		97		—
Total equity securities	710		613		97		—
Other investments	55		16		—		39
Total	$	62,750	$	2,786	$	59,716	$	248

(at December 31, 2015, 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	$	2,194	$	2,194	$	—	$	—
Obligations of states, municipalities and political subdivisions	31,411		—		31,398		13
Debt securities issued by foreign governments	1,873		—		1,873		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,981		—		1,957		24
All other corporate bonds	23,089		—		22,915		174
Redeemable preferred stock	110		3		100		7
Total fixed maturities	60,658		2,197		58,243		218
Equity securities
Public common stock	543		543		—		—
Non-redeemable preferred stock	162		55		107		—
Total equity securities	705		598		107		—
Other investments	56		18		—		38
Total	$	61,419	$	2,813	$	58,350	$	256

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 categorized [Table Text Block]

(at March 31, 2016, in millions)	Carrying Value		Fair Value		Level 1		Level 2		Level 3
Financial assets:
Short-term securities	$	4,587	$	4,587	$	1,174	$	3,378	$	35
Financial liabilities:
Debt	$	6,244	$	7,419	$	—	$	7,419	$	—
Commercial paper	$	100	$	100	$	—	$	100	$	—

(at December 31, 2015, in millions)	Carrying Value		Fair Value		Level 1		Level 2		Level 3
Financial assets:
Short-term securities	$	4,671	$	4,671	$	1,685	$	2,958	$	28
Financial liabilities:
Debt	$	6,244	$	7,180	$	—	$	7,180	$	—
Commercial paper	$	100	$	100	$	—	$	100	$	—