Fair Value of Assets and Liabilities (Balances of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	$ 4,203,450		$ 5,273,767
Trading account assets, at fair value	7,916		38,578
Equity securities, available for sale	22		3,071
Other assets	1,995
Separate account assets	44,601,720		42,942,758
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	4,203,450		5,273,767
Trading account assets, at fair value	7,916		38,578
Equity securities, available for sale	22		3,071
Short-term investments	103,761		237,601
Cash equivalents	0		8,112
Other long-term investments	132,051		152,345
Reinsurance recoverable	1,732,094		1,747,757
Other assets	22,627		25,225
Subtotal excluding separate account assets	6,201,921		7,486,456
Separate account assets	44,601,720	[1]	42,942,758	[1]
Total assets	50,803,641		50,429,214
Future policy benefits	1,793,137		1,783,595
Other liabilities	0		0
Total liabilities	1,793,137		1,783,595
US Treasury And Government [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	4,686		86,036
Obligations of U.S. states and their political subdivisions [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	102,116		94,158
Foreign Government Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	55,529		77,230
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	3,191,254		3,951,209
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	187,477		177,384
Trading account assets, at fair value	2,022		31,571
Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	394,902		491,757
Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	267,486		395,993
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets, at fair value	5,894		7,007
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		6,705
Trading account assets, at fair value	5,687		6,804
Equity securities, available for sale	0		3,071
Short-term investments	103,761		227,235
Cash equivalents	0		8,112
Other long-term investments	0		0
Reinsurance recoverable	0		0
Other assets	0		0
Subtotal excluding separate account assets	109,448		251,927
Separate account assets	122,142	[1]	1,039,821	[1]
Total assets	231,590		1,291,748
Future policy benefits	0		0
Other liabilities	0		0
Total liabilities	0		0
Fair Value, Inputs, Level 1 [Member] | US Treasury And Government [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Fair Value, Inputs, Level 1 [Member] | Obligations of U.S. states and their political subdivisions [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Fair Value, Inputs, Level 1 [Member] | Foreign Government Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		6,705
Fair Value, Inputs, Level 1 [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Trading account assets, at fair value	0		0
Fair Value, Inputs, Level 1 [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Fair Value, Inputs, Level 1 [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets, at fair value	5,687		6,804
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	4,038,597		5,128,841
Trading account assets, at fair value	2,022		31,571
Equity securities, available for sale	22		0
Short-term investments	0		10,366
Cash equivalents	0		0
Other long-term investments	173,348		191,144
Reinsurance recoverable	0		0
Other assets	20,632		25,225
Subtotal excluding separate account assets	4,234,621		5,387,147
Separate account assets	44,479,578	[1]	41,902,937	[1]
Total assets	48,714,199		47,290,084
Future policy benefits	0		0
Other liabilities	42,351		40,012
Total liabilities	42,351		40,012
Fair Value, Inputs, Level 2 [Member] | US Treasury And Government [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	4,686		86,036
Fair Value, Inputs, Level 2 [Member] | Obligations of U.S. states and their political subdivisions [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	102,116		94,158
Fair Value, Inputs, Level 2 [Member] | Foreign Government Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	55,529		77,230
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	3,095,699		3,854,846
Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	118,179		128,821
Trading account assets, at fair value	2,022		31,571
Fair Value, Inputs, Level 2 [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	394,902		491,757
Fair Value, Inputs, Level 2 [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	267,486		395,993
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets, at fair value	0		0
Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other long-term investments	1,054
Reinsurance recoverable	1,732,094
Total assets	1,900,203
Future policy benefits	1,793,137
Total liabilities	1,793,137
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	164,853		138,221
Trading account assets, at fair value	207		203
Equity securities, available for sale	0		0
Short-term investments	0		0
Cash equivalents	0		0
Other long-term investments	1,054		1,213
Reinsurance recoverable	1,732,094		1,747,757
Other assets	1,995		0
Subtotal excluding separate account assets	1,900,203		1,887,394
Separate account assets	0	[1]	0	[1]
Total assets	1,900,203		1,887,394
Future policy benefits	1,793,137		1,783,595
Other liabilities	0		0
Total liabilities	1,793,137		1,783,595
Fair Value, Inputs, Level 3 [Member] | US Treasury And Government [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Fair Value, Inputs, Level 3 [Member] | Obligations of U.S. states and their political subdivisions [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Fair Value, Inputs, Level 3 [Member] | Foreign Government Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	95,555		89,658
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	69,298		48,563
Trading account assets, at fair value	0		0
Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Fair Value, Inputs, Level 3 [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0		0
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets, at fair value	207		203
Netting And Collateral [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0	[2]	0
Trading account assets, at fair value	0	[2]	0
Equity securities, available for sale	0	[2]	0
Short-term investments	0	[2]	0
Cash equivalents	0	[2]	0
Other long-term investments	(42,351)	[2]	(40,012)
Reinsurance recoverable	0	[2]	0
Other assets	0	[2]	0
Subtotal excluding separate account assets	(42,351)	[2]	(40,012)
Separate account assets	0	[1],[2]	0	[1]
Total assets	(42,351)	[2]	(40,012)
Future policy benefits	0	[2]	0
Other liabilities	(42,351)	[2]	(40,012)
Total liabilities	(42,351)	[2]	(40,012)
Netting And Collateral [Member] | US Treasury And Government [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0	[2]	0
Netting And Collateral [Member] | Obligations of U.S. states and their political subdivisions [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0	[2]	0
Netting And Collateral [Member] | Foreign Government Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0	[2]	0
Netting And Collateral [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0	[2]	0
Netting And Collateral [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0	[2]	0
Trading account assets, at fair value	0	[2]	0
Netting And Collateral [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0	[2]	0
Netting And Collateral [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities, available for sale, at fair value	0	[2]	0
Netting And Collateral [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets, at fair value	$ 0	[2]	$ 0

[1] Separate account assets represent segregated funds that are invested for certain customers. Investment risks associated with market value changes are borne by the customers, except to the extent of minimum guarantees made by the Company with respect to certain accounts. Separate account liabilities are not included in the above table as they are reported at contract value and not fair value in the Company’s Statements of Financial Position.

[2] “Netting” amounts represent the impact of offsetting asset and liability positions held with the same counterparty.