Fair Value of Assets and Liabilities (Level 3 by Pricing Source) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Separate account assets	$ 44,111,486		$ 44,101,699
Receivables from parents and affiliates	59,703		60,490
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other long-term investments	139,839		95,191
Reinsurance recoverable	3,300,612		2,996,154
Subtotal excluding separate account assets	6,282,665		5,996,564
Separate account assets	44,111,486	[1]	44,101,699	[1]
Total assets	50,394,151		50,098,263
Future policy benefits	3,430,249	[2]	3,112,411	[2]
Total liabilities	3,430,249		3,112,411
Receivables from parents and affiliates	40,783		41,068
Cash equivalents	225
Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable Securities, Equity Securities	0
Other long-term investments	635		633
Reinsurance recoverable	3,300,612		2,996,154
Total assets	3,492,647		3,175,926
Future policy benefits	3,430,249		3,112,411
Total liabilities	3,430,249		3,112,411
Receivables from parents and affiliates	24,015		22,320
Cash equivalents	225		225
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	[3]
Other long-term investments	0	[3]	0	[3]
Reinsurance recoverable	3,300,612	[3]	2,996,154	[3]
Total assets	3,402,432	[3]	3,095,588	[3]
Future policy benefits	3,430,249	[3]	3,112,411	[3]
Total liabilities	3,430,249	[3]	3,112,411	[3]
Receivables from parents and affiliates	0	[3]	0	[3]
Cash equivalents	225	[3]	225	[3]
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	0	[4]
Other long-term investments	635	[4]	633	[4]
Reinsurance recoverable	0	[4]	0	[4]
Total assets	90,215	[4]	80,338	[4]
Future policy benefits	0	[4]	0	[4]
Total liabilities	0	[4]	0	[4]
Receivables from parents and affiliates	24,015	[4]	22,320	[4]
Cash equivalents	0	[4]	0	[4]
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	635		633
Reinsurance recoverable	3,300,612		2,996,154
Subtotal excluding separate account assets	3,492,647		3,175,926
Separate account assets	0	[1]	0	[1]
Total assets	3,492,647		3,175,926
Future policy benefits	3,430,249	[2]	3,112,411	[2]
Total liabilities	3,430,249		3,112,411
Receivables from parents and affiliates	24,015		22,320
Cash equivalents	225
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	118,322		116,070
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	101,595	[3]	99,209	[3]
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	16,727	[4]	16,861	[4]
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	48,838		40,524
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	[3]	0	[3]
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	48,838	[4]	40,524	[4]
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	0
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	[3]
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	$ 0	[4]

[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] As of March 31, 2015, the net embedded derivative liability position of $3,430 million includes $41 million of embedded derivatives in an asset position and $3,471 million of embedded derivatives in a liability position. As of December 31, 2014, the net embedded derivative liability position of $3,112 million includes $55 million of embedded derivatives in an asset position and $3,167 million of embedded derivatives in a liability position.

[3] 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.

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