Investments (tables)

12 Months Ended

Dec. 31, 2011

Investments disclosure

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

			Gross Unrealized
	Amortized Cost						Fair Value
(at December 31, 2011, in millions)			Gains		Losses
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,396	$	101	$	—	$	2,497
Obligations of states, municipalities and political subdivisions:
Pre-refunded		6,820		513		1		7,332
All other		29,391		2,303		4		31,690
Total obligations of states, municipalities and political subdivisions		36,211		2,816		5		39,022
Debt securities issued by foreign governments		2,228		91		1		2,318
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities		3,288		249		22		3,515
All other corporate bonds		15,845		1,066		61		16,850
Redeemable preferred stock		26		4		—		30
Total	$	59,994	$	4,327	$	89	$	64,232

			Gross Unrealized
	Amortized Cost						Fair Value
(at December 31, 2010, in millions)			Gains		Losses
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	1,914	$	94	$	—	$	2,008
Obligations of states, municipalities and political subdivisions:
Pre-refunded		6,787		505		1		7,291
All other		31,277		1,121		154		32,244
Total obligations of states, municipalities and political subdivisions		38,064		1,626		155		39,535
Debt securities issued by foreign governments		2,156		50		4		2,202
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities		3,952		248		36		4,164
All other corporate bonds		14,051		876		51		14,876
Redeemable preferred stock		33		2		—		35
Total	$	60,170	$	2,896	$	246	$	62,820

Amortized cost and fair value of fixed maturities by contractual maturity [Table Text Block]

(at December 31, 2011, in millions)	Amortized Cost		Fair Value
Due in one year or less	$	5,829	$	5,901
Due after 1 year through 5 years		19,843		21,144
Due after 5 years through 10 years		17,107		18,694
Due after 10 years		13,927		14,978
		56,706		60,717
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities		3,288		3,515
Total	$	59,994	$	64,232

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

			Gross Unrealized
							Fair Value
(at December 31, 2011, in millions)	Cost		Gains		Losses
Common stock	$	311	$	120	$	3	$	428
Non-redeemable preferred stock		103		29		1		131
Total	$	414	$	149	$	4	$	559

			Gross Unrealized
							Fair Value
(at December 31, 2010, in millions)	Cost		Gains		Losses
Common stock	$	198	$	106	$	—	$	304
Non-redeemable preferred stock		174		46		5		215
Total	$	372	$	152	$	5	$	519

Unrealized investment losses [Table Text Block]

	Less than 12 months				12 months or longer				Total
(at December 31, 2011, 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	$	356	$	—	$	—	$	—	$	356	$	—
Obligations of states, municipalities and political subdivisions		27		—		191		5		218		5
Debt securities issued by foreign governments		96		1		2		—		98		1
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities		362		12		155		10		517		22
All other corporate bonds		1,295		42		105		19		1,400		61
Total fixed maturities		2,136		55		453		34		2,589		89
Equity securities
Common stock		64		3		—		—		64		3
Non-redeemable preferred stock		37		1		7		—		44		1
Total equity securities		101		4		7		—		108		4
Total	$	2,237	$	59	$	460	$	34	$	2,697	$	93

	Less than 12 months				12 months or longer				Total
(at December 31, 2010, 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	$	155	$	—	$	—	$	—	$	155	$	—
Obligations of states, municipalities and political subdivisions		5,364		149		139		6		5,503		155
Debt securities issued by foreign governments		419		4		13		—		432		4
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities		77		1		420		35		497		36
All other corporate bonds		1,230		32		185		19		1,415		51
Redeemable preferred stock		—		—		3		—		3		—
Total fixed maturities		7,245		186		760		60		8,005		246
Equity securities
Common stock		3		—		3		—		6		—
Non-redeemable preferred stock		45		1		49		4		94		5
Total equity securities		48		1		52		4		100		5
Total	$	7,293	$	187	$	812	$	64	$	8,105	$	251

Securities continuously in an unrealized loss position of greater than 20% of amortized cost by length of time [Table Text Block]

	Period For Which Fair Value Is Less Than 80% of Amortized Cost
(in millions)	3 Months or Less		Greater Than 3 Months, 6 Months or Less		Greater Than 6 Months, 12 Months or Less		Greater Than 12 Months		Total
Fixed maturities:
Mortgage-backed securities	$	2	$	—	$	—	$	—	$	2
Other		—		5		6		9		20
Total fixed maturities		2		5		6		9		22
Equity securities		—		—		—		—		—
Total	$	2	$	5	$	6	$	9	$	22

Impairment charges included in net realized investment gains [Table Text Block]

(for the year ended December 31, in millions)	2011		2010		2009
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	—	$	—	$	—
Obligations of states, municipalities and political subdivisions		—		—		—
Debt securities issued by foreign governments		—		—		—
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities		13		4		81
All other corporate bonds		5		9		88
Redeemable preferred stock		—		—		—
Total fixed maturities		18		13		169
Equity securities
Common stock		6		2		15
Non-redeemable preferred stock		—		1		64
Total equity securities		6		3		79
Other investments		1		10		10
Total	$	25	$	26	$	258

Roll-forward of the credit component of other-than-temporary impairments on fixed maturities recognized in the consolidated statement of income for which a portion of the other-than-temporary impairment was recognized in accumulated other changes in equity from nonowner sources [Table Text Block]

Year ended December 31, 2011 (in millions)	Cumulative OTTI Credit Losses Recognized for Securities Held, Beginning of Period		Additions for OTTI Securities Where No Credit Losses Were Previously Recognized		Additions for OTTI Securities Where Credit Losses Have Been Previously Recognized		Reductions Due to Sales/Defaults of Credit- Impaired Securities			Adjustments to Book Value of Credit- Impaired Securities due to Changes in Cash Flows			Cumulative OTTI Credit Losses Recognized for Securities Still Held, End of Period
Fixed maturities
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	$	47	$	—	$	12	$	—		$	(1	)	$	58
All other corporate bonds		88		2		2		(4	)		6			94
Total fixed maturities	$	135	$	2	$	14	$	(4	)	$	5		$	152

Year ended December 31, 2010 (in millions)	Cumulative OTTI Credit Losses Recognized for Securities Held, Beginning of Period		Additions for OTTI Securities Where No Credit Losses Were Previously Recognized		Additions for OTTI Securities Where Credit Losses Have Been Previously Recognized		Reductions Due to Sales/Defaults of Credit- Impaired Securities			Adjustments to Book Value of Credit- Impaired Securities due to Changes in Cash Flows		Cumulative OTTI Credit Losses Recognized for Securities Still Held, End of Period
Fixed maturities
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	$	46	$	—	$	4	$	(3	)	$	—	$	47
All other corporate bonds		93		—		5		(13	)		3		88
Total fixed maturities	$	139	$	—	$	9	$	(16	)	$	3	$	135

Net investment income [Table Text Block]

(for the year ended December 31, in millions)	2011		2010		2009
Gross investment income (loss)
Fixed maturities	$	2,543	$	2,710	$	2,822
Equity securities		29		31		30
Short-term securities		12		13		27
Real estate		34		35		36
Other investments		292		304		(106	)
Gross investment income		2,910		3,093		2,809
Investment expenses		31		34		33
Net investment income	$	2,879	$	3,059	$	2,776

Change in net unrealized investment gains (losses) [Table Text Block]

(at and for the year ended December 31, in millions)	2011			2010			2009
Change in net unrealized investment gains (losses)
Fixed maturities	$	1,588		$	114		$	2,830
Equity securities		(2	)		69			160
Other investments		(14	)		(178	)		87
		1,572			5			3,077
Related tax expense		560			2			1,075
Change in net unrealized gain on investment securities		1,012			3			2,002
Balance, beginning of year		1,859			1,856			(146	)
Balance, end of year	$	2,871		$	1,859		$	1,856