Investments (tables)

6 Months Ended

Jun. 30, 2016

Investments disclosure

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

	Amortized		Gross Unrealized				Fair
(at June 30, 2016, in millions)	Cost		Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,038	$	36	$	1	$	2,073
Obligations of states, municipalities and political subdivisions:
Local general obligation	13,816		954		1		14,769
Revenue	10,270		787		—		11,057
State general obligation	1,958		124		—		2,082
Pre-refunded	5,490		234		—		5,724
Total obligations of states, municipalities and political subdivisions	31,534		2,099		1		33,632
Debt securities issued by foreign governments	1,745		56		—		1,801
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,702		132		1		1,833
All other corporate bonds	22,858		1,062		52		23,868
Redeemable preferred stock	98		6		—		104
Total	$	59,975	$	3,391	$	55	$	63,311

	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 June 30, 2016, in millions)	Cost		Gains		Losses		Value
Public common stock	$	386	$	214	$	3	$	597
Non-redeemable preferred stock	139		23		7		155
Total	$	525	$	237	$	10	$	752

			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 June 30, 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	$	37	$	—	$	10	$	1	$	47	$	1
Obligations of states, municipalities and political subdivisions	639		1		14		—		653		1
Debt securities issued by foreign governments	3		—		—		—		3		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	42		—		37		1		79		1
All other corporate bonds	779		12		720		40		1,499		52
Redeemable preferred stock	7		—		—		—		7		—
Total fixed maturities	1,507		13		781		42		2,288		55
Equity securities
Public common stock	24		2		34		1		58		3
Non-redeemable preferred stock	30		1		58		6		88		7
Total equity securities	54		3		92		7		146		10
Total	$	1,561	$	16	$	873	$	49	$	2,434	$	65

	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