Investments OTTI (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2012 securities		Jun. 30, 2011 securities		Jun. 30, 2012 securities		Jun. 30, 2011 securities		Dec. 31, 2011
Available-for-sale Securities Including Securities Pledged [Line Items]
Impairment	$ 1,700,000		$ 17,800,000		$ 3,000,000		$ 38,000,000
No. of Securities	29		50		35		86
Fair value of fixed maturies with OTTI	1,700,000,000				1,700,000,000				1,800,000,000
U.S. corporate securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Impairment	200,000		300,000		200,000		3,900,000
No. of Securities	1		1		1		2
Foreign
Available-for-sale Securities Including Securities Pledged [Line Items]
Impairment	400,000	[1]	200,000	[1]	800,000	[1]	3,300,000	[1]
No. of Securities	2		2	[1]	3		11
Residential mortgage-backed
Available-for-sale Securities Including Securities Pledged [Line Items]
Impairment	900,000		3,000,000		1,600,000		3,300,000
No. of Securities	24		18		28		23
Commercial mortgage-backed
Available-for-sale Securities Including Securities Pledged [Line Items]
Impairment	0		8,100,000		0		8,100,000
No. of Securities	0		3		0		3
Other asset-backed securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Impairment	200,000		6,200,000		400,000		19,400,000
No. of Securities	2		26		3		47
Credit related impairment
Available-for-sale Securities Including Securities Pledged [Line Items]
Write-downs related to credit impairments	1,100,000		3,600,000		1,900,000		6,400,000
Intent related impairment
Available-for-sale Securities Including Securities Pledged [Line Items]
No. of Securities	3		30		5		59
Write-down related to intent impairments	600,000		14,200,000		1,100,000		31,600,000
Intent related impairment | U.S. corporate securities
Available-for-sale Securities Including Securities Pledged [Line Items]
No. of Securities	1				1		2
Write-down related to intent impairments	200,000		300,000		200,000		3,900,000
Intent related impairment | Foreign
Available-for-sale Securities Including Securities Pledged [Line Items]
No. of Securities	2	[1]			3	[1]	8	[1]
Write-down related to intent impairments	400,000	[1]	200,000	[1]	800,000	[1]	1,200,000	[1]
Intent related impairment | Residential mortgage-backed
Available-for-sale Securities Including Securities Pledged [Line Items]
No. of Securities	0		0		0		1
Write-down related to intent impairments	0		0		0		100,000
Intent related impairment | Commercial mortgage-backed
Available-for-sale Securities Including Securities Pledged [Line Items]
No. of Securities	0		3		0		3
Write-down related to intent impairments	0		8,100,000		0		8,100,000
Intent related impairment | Other asset-backed securities
Available-for-sale Securities Including Securities Pledged [Line Items]
No. of Securities	0		24		1		45
Write-down related to intent impairments	$ 0		$ 5,600,000		$ 100,000		$ 18,300,000

[1] Primarily U.S. dollar denominated.