Fair Value of Assets and Liabilities (Level 3 by Pricing Source) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Separate account assets	$ 45,134,054		$ 42,942,758
Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other long-term investments	1,442	[1]
External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other long-term investments	315	[1]
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other long-term investments	165,305		152,345	[2]
Reinsurance recoverable	1,822,323		1,747,757	[2]
Subtotal excluding separate account assets	6,723,950		7,486,456	[2]
Separate account assets	45,134,054	[3]	42,942,758	[2],[3]
Total assets	51,858,004		50,429,214	[2]
Future policy benefits	1,886,648		1,783,595	[2]
Total liabilities	1,886,648		1,783,595	[2]
Fair Value, Measurements, Recurring [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Equity Securities	0	[1]
Reinsurance recoverable	1,822,323	[1]
Total assets	1,915,828	[1]
Future policy benefits	1,886,648	[1]
Total liabilities	1,886,648	[1]
Fair Value, Measurements, Recurring [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Equity Securities	195	[4]
Reinsurance recoverable	0	[4]
Total assets	61,540	[4]
Future policy benefits	0	[4]
Total liabilities	0	[4]
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	92,063	[1]
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	3,327	[4]
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Internal Pricing [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	0	[1]
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | External Priced [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Fixed Maturities	57,703	[4]
Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Equity Securities	195
Other long-term investments	1,757
Reinsurance recoverable	1,822,323
Total assets	1,977,368
Future policy benefits	1,886,648
Total liabilities	1,886,648
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	1,757		1,213	[2]
Reinsurance recoverable	1,822,323		1,747,757	[2]
Subtotal excluding separate account assets	1,977,368		1,887,394	[2]
Separate account assets	0	[3]	0	[2],[3]
Total assets	1,977,368		1,887,394	[2]
Future policy benefits	1,886,648		1,783,595	[2]
Total liabilities	1,886,648		1,783,595	[2]
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	95,390
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	$ 57,703

[1] 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.

[2] Includes reclassifications to conform to current period presentation.

[3] 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.

[4] Represents unadjusted prices from independent pricing services and independent indicative broker quotes where pricing inputs are not readily available.