Investments (tables)

3 Months Ended

Mar. 31, 2016

Investments disclosure

Amortized cost and fair value of investments in fixed maturities [Table Text Block]

	Amortized		Gross Unrealized				Fair
(at March 31, 2016, in millions)	Cost		Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,128	$	27	$	1	$	2,154
Obligations of states, municipalities and political subdivisions:
Local general obligation	13,242		690		1		13,931
Revenue	9,914		563		3		10,474
State general obligation	1,944		102		—		2,046
Pre-refunded	5,640		231		—		5,871
Total obligations of states, municipalities and political subdivisions	30,740		1,586		4		32,322
Debt securities issued by foreign governments	1,794		52		—		1,846
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,799		131		1		1,929
All other corporate bonds	22,921		834		135		23,620
Redeemable preferred stock	108		6		—		114
Total	$	59,490	$	2,636	$	141	$	61,985

	Amortized		Gross Unrealized				Fair
(at December 31, 2015, in millions)	Cost		Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,202	$	8	$	16	$	2,194
Obligations of states, municipalities and political subdivisions:
Local general obligation	12,744		577		3		13,318
Revenue	9,492		472		4		9,960
State general obligation	1,978		97		2		2,073
Pre-refunded	5,813		247		—		6,060
Total obligations of states, municipalities and political subdivisions	30,027		1,393		9		31,411
Debt securities issued by foreign governments	1,829		45		1		1,873
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,863		124		6		1,981
All other corporate bonds	22,854		523		288		23,089
Redeemable preferred stock	103		7		—		110
Total	$	58,878	$	2,100	$	320	$	60,658

Cost and fair value of investments in equity securities [Table Text Block]

			Gross Unrealized				Fair
(at March 31, 2016, in millions)	Cost		Gains		Losses		Value
Public common stock	$	383	$	174	$	8	$	549
Non-redeemable preferred stock	145		24		8		161
Total	$	528	$	198	$	16	$	710

			Gross Unrealized				Fair
(at December 31, 2015, in millions)	Cost		Gains		Losses		Value
Public common stock	$	386	$	164	$	7	$	543
Non-redeemable preferred stock	142		26		6		162
Total	$	528	$	190	$	13	$	705

Unrealized investment losses [Table Text Block]

	Less than 12 months				12 months or longer				Total
(at March 31, 2016, in millions)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	171	$	—	$	10	$	1	$	181	$	1
Obligations of states, municipalities and political subdivisions	681		3		141		1		822		4
Debt securities issued by foreign governments	25		—		—		—		25		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	98		—		73		1		171		1
All other corporate bonds	2,010		70		941		65		2,951		135
Redeemable preferred stock	22		—		—		—		22		—
Total fixed maturities	3,007		73		1,165		68		4,172		141
Equity securities
Public common stock	54		8		34		—		88		8
Non-redeemable preferred stock	29		1		59		7		88		8
Total equity securities	83		9		93		7		176		16
Total	$	3,090	$	82	$	1,258	$	75	$	4,348	$	157

	Less than 12 months				12 months or longer				Total
(at December 31, 2015, in millions)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	1,820	$	15	$	28	$	1	$	1,848	$	16
Obligations of states, municipalities and political subdivisions	928		7		142		2		1,070		9
Debt securities issued by foreign governments	172		1		—		—		172		1
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	473		4		57		2		530		6
All other corporate bonds	7,725		197		710		91		8,435		288
Redeemable preferred stock	8		—		—		—		8		—
Total fixed maturities	11,126		224		937		96		12,063		320
Equity securities
Public common stock	48		6		33		1		81		7
Non-redeemable preferred stock	47		3		38		3		85		6
Total equity securities	95		9		71		4		166		13
Total	$	11,221	$	233	$	1,008	$	100	$	12,229	$	333