Investments (Details 7) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Investments in limited partnerships
Equity in earnings of limited partnerships	$ 27,000,000	$ 39,000,000	$ 77,000,000	$ 75,000,000
Asset recorded	1,072,000,000		1,072,000,000		1,086,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			7,000,000		(28,000,000)
Income (loss) recorded			70,000,000		189,000,000
Per the limited partner financial statements
Total partnership assets	47,000,000,000		47,000,000,000		50,000,000,000
Total partnership liabilities	4,000,000,000		4,000,000,000		5,000,000,000
Total partnership valuation adjustment gains (losses)			500,000,000		2,000,000,000
Total partnership net income			3,000,000,000		7,000,000,000
Indemnity
Investments in limited partnerships
Equity in earnings of limited partnerships	3,000,000	5,000,000	9,000,000	8,000,000
Number of partnerships	58		58		61
Asset recorded	141,000,000		141,000,000		146,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			3,000,000		(3,000,000)
Income (loss) recorded			6,000,000		25,000,000
Indemnity | Private equity
Investments in limited partnerships
Number of partnerships	27		27		29
Asset recorded	58,000,000		58,000,000		62,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			0		(3,000,000)
Income (loss) recorded			4,000,000		9,000,000
Indemnity | Private equity | Less than 10%
Investments in limited partnerships
Number of partnerships	24		24		26
Asset recorded	39,000,000		39,000,000		46,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			(3,000,000)		(6,000,000)
Income (loss) recorded			4,000,000		9,000,000
Indemnity | Private equity | Greater than or equal to 10% but less than 50%
Investments in limited partnerships
Number of partnerships	3		3		3
Asset recorded	19,000,000		19,000,000		16,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			3,000,000		3,000,000
Income (loss) recorded			0		0
Indemnity | Private equity | Greater than 50%
Investments in limited partnerships
Number of partnerships	0		0		0
Asset recorded	0		0		0
Income (loss) recognized due to valuation adjustments by the partnerships			0		0
Income (loss) recorded			0		0
Indemnity | Mezzanine debt
Investments in limited partnerships
Number of partnerships	15		15		15
Asset recorded	18,000,000		18,000,000		20,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			0		0
Income (loss) recorded			1,000,000		3,000,000
Indemnity | Mezzanine debt | Less than 10%
Investments in limited partnerships
Number of partnerships	11		11		11
Asset recorded	12,000,000		12,000,000		14,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			0		0
Income (loss) recorded			1,000,000		1,000,000
Indemnity | Mezzanine debt | Greater than or equal to 10% but less than 50%
Investments in limited partnerships
Number of partnerships	3		3		3
Asset recorded	6,000,000		6,000,000		6,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			0		0
Income (loss) recorded			0		2,000,000
Indemnity | Mezzanine debt | Greater than 50%
Investments in limited partnerships
Number of partnerships	1		1		1
Asset recorded	0		0		0
Income (loss) recognized due to valuation adjustments by the partnerships			0		0
Income (loss) recorded			0		0
Indemnity | Real estate
Investments in limited partnerships
Number of partnerships	16		16		17
Asset recorded	65,000,000		65,000,000		64,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			3,000,000		0
Income (loss) recorded			1,000,000		13,000,000
Indemnity | Real estate | Less than 10%
Investments in limited partnerships
Number of partnerships	11		11		12
Asset recorded	44,000,000		44,000,000		44,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			2,000,000		0
Income (loss) recorded			1,000,000		5,000,000
Indemnity | Real estate | Greater than or equal to 10% but less than 50%
Investments in limited partnerships
Number of partnerships	3		3		3
Asset recorded	15,000,000		15,000,000		14,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			1,000,000		(1,000,000)
Income (loss) recorded			0		4,000,000
Indemnity | Real estate | Greater than 50%
Investments in limited partnerships
Number of partnerships	2		2		2
Asset recorded	6,000,000		6,000,000		6,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			0		1,000,000
Income (loss) recorded			0		4,000,000
Exchange
Investments in limited partnerships
Equity in earnings of limited partnerships	24,000,000	34,000,000	68,000,000	67,000,000
Number of partnerships	100		100		103
Asset recorded	931,000,000		931,000,000		940,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			4,000,000		(25,000,000)
Income (loss) recorded			64,000,000		164,000,000
Exchange | Private equity
Investments in limited partnerships
Number of partnerships	45		45		47
Asset recorded	448,000,000		448,000,000		463,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			8,000,000		(11,000,000)
Income (loss) recorded			25,000,000		81,000,000
Exchange | Private equity | Less than 10%
Investments in limited partnerships
Number of partnerships	42		42		44
Asset recorded	368,000,000		368,000,000		396,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			(7,000,000)		(24,000,000)
Income (loss) recorded			24,000,000		79,000,000
Exchange | Private equity | Greater than or equal to 10% but less than 50%
Investments in limited partnerships
Number of partnerships	3		3		3
Asset recorded	80,000,000		80,000,000		67,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			15,000,000		13,000,000
Income (loss) recorded			1,000,000		2,000,000
Exchange | Private equity | Greater than 50%
Investments in limited partnerships
Number of partnerships	0		0		0
Asset recorded	0		0		0
Income (loss) recognized due to valuation adjustments by the partnerships			0		0
Income (loss) recorded			0		0
Exchange | Mezzanine debt
Investments in limited partnerships
Number of partnerships	27		27		26
Asset recorded	167,000,000		167,000,000		172,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			(1,000,000)		(1,000,000)
Income (loss) recorded			12,000,000		23,000,000
Exchange | Mezzanine debt | Less than 10%
Investments in limited partnerships
Number of partnerships	20		20		19
Asset recorded	113,000,000		113,000,000		117,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			1,000,000		1,000,000
Income (loss) recorded			9,000,000		13,000,000
Exchange | Mezzanine debt | Greater than or equal to 10% but less than 50%
Investments in limited partnerships
Number of partnerships	4		4		4
Asset recorded	23,000,000		23,000,000		23,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			(2,000,000)		(3,000,000)
Income (loss) recorded			2,000,000		7,000,000
Exchange | Mezzanine debt | Greater than 50%
Investments in limited partnerships
Number of partnerships	3		3		3
Asset recorded	31,000,000		31,000,000		32,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			0		1,000,000
Income (loss) recorded			1,000,000		3,000,000
Exchange | Real estate
Investments in limited partnerships
Number of partnerships	28		28		30
Asset recorded	316,000,000		316,000,000		305,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			(3,000,000)		(13,000,000)
Income (loss) recorded			27,000,000		60,000,000
Exchange | Real estate | Less than 10%
Investments in limited partnerships
Number of partnerships	20		20		22
Asset recorded	215,000,000		215,000,000		211,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			8,000,000		(10,000,000)
Income (loss) recorded			10,000,000		34,000,000
Exchange | Real estate | Greater than or equal to 10% but less than 50%
Investments in limited partnerships
Number of partnerships	6		6		6
Asset recorded	77,000,000		77,000,000		71,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			3,000,000		(2,000,000)
Income (loss) recorded			1,000,000		10,000,000
Exchange | Real estate | Greater than 50%
Investments in limited partnerships
Number of partnerships	2		2		2
Asset recorded	24,000,000		24,000,000		23,000,000
Income (loss) recognized due to valuation adjustments by the partnerships			(14,000,000)		(1,000,000)
Income (loss) recorded			$ 16,000,000		$ 16,000,000