Fair Value of Assets and Liabilities (Level 3 by Pricing Source) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Separate account assets	$ 45,745,140		$ 44,601,720
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other long-term investments	89,054		132,051
Reinsurance recoverable	1,191,409		1,732,094
Subtotal excluding separate account assets	5,395,879		6,201,921
Separate account assets	45,745,140	[1]	44,601,720	[1]
Total assets	51,141,019		50,803,641
Future policy benefits	1,230,323		1,793,137
Total liabilities	1,230,323		1,793,137
Other assets	22,315		22,627
Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Equity Securities	267		207
Other long-term investments	463		1,054
Reinsurance recoverable	1,191,409		1,732,094
Total assets	1,371,561		1,900,203
Future policy benefits	1,230,323		1,793,137
Total liabilities	1,230,323		1,793,137
Other assets	2,000		1,995
Fair Value, Inputs, Level 3 [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Equity Securities	0	[2]	0	[2]
Other long-term investments	116	[2]	739	[2]
Reinsurance recoverable	1,191,409	[2]	1,732,094	[2]
Total assets	1,285,009	[2]	1,825,096	[2]
Future policy benefits	1,230,323	[2]	1,793,137	[2]
Total liabilities	1,230,323	[2]	1,793,137	[2]
Other assets	0	[2]	0	[2]
Fair Value, Inputs, Level 3 [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Equity Securities	267	[3]	207	[3]
Other long-term investments	347	[3]	315	[3]
Reinsurance recoverable	0	[3]	0	[3]
Total assets	86,552	[3]	75,107	[3]
Future policy benefits	0	[3]	0	[3]
Total liabilities	0	[3]	0	[3]
Other assets	2,000	[3]	1,995	[3]
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other long-term investments	463		1,054
Reinsurance recoverable	1,191,409		1,732,094
Subtotal excluding separate account assets	1,371,561		1,900,203
Separate account assets	0	[1]	0	[1]
Total assets	1,371,561		1,900,203
Future policy benefits	1,230,323		1,793,137
Total liabilities	1,230,323		1,793,137
Other assets	2,000		1,995
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	95,575		95,555
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	93,484	[2]	92,263	[2]
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	2,091	[3]	3,292	[3]
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	72,740		69,298
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	0	[2]	0	[2]
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	72,740	[3]	69,298	[3]
Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	9,107
Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	0	[2]
Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	$ 9,107	[3]

[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 Unaudited Interim Statements of Financial Position.

[2] Represents valuations reflecting both internally-derived and market inputs, as well as third-party pricing information or quotes. See below for additional information related to internally-developed valuation for significant items in the above table.

[3] Represents unadjusted prices from independent pricing services and independent non-binding broker quotes where pricing inputs are not readily available.