Accumulated Other Comprehensive Income (Schedule of Reclassifications out of AOCI) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Investment related gains (losses), net	$ 84,874		$ 94,573
Investment income	404,375		425,131
Total before tax	199,440		278,827
Tax (expense) benefit	(62,776)		(93,292)
Net income	136,664		185,535
Unrealized Appreciation Depreciation Of Investments [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total before tax	5,828		9,105
Tax (expense) benefit	(1,904)		(2,934)
Net income	3,924		6,171
Unrealized Appreciation Depreciation Of Investments [Member] | Unrealized Gains Losses On Available For Sale Securities [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Investment related gains (losses), net	1,189		10,348
Unrealized Appreciation Depreciation Of Investments [Member] | Gains Losses On Qualifying Cash Flow Hedging Instruments [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Investment income	218		305
Unrealized Appreciation Depreciation Of Investments [Member] | DAC Attributed To Unrealized Gains Losses [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Deferred policy acquisition costs attributed to unrealized gains and losses	4,421	[1]	(1,548)	[1]
Amortization Of Unrealized Pension And Postretirement Benefits [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total before tax	(892)		(1,117)
Tax (expense) benefit	312		391
Net income	(580)		(726)
Amounts Reclassified From AOCI [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net income	3,344		5,445
Prior Service Cost [Member] | Amortization Of Unrealized Pension And Postretirement Benefits [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Prior service cost	(2)	[2]	(94)	[2]
Actuarial Gains Losses [Member] | Amortization Of Unrealized Pension And Postretirement Benefits [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Actuarial gains/(losses)	$ (890)	[2]	$ (1,023)	[2]

[1] This AOCI component is included in the computation of the deferred policy acquisition cost. See Note 8 – “Deferred Policy Acquisition Costs” of the 2013 Annual Report for additional details.

[2] These AOCI components are included in the computation of the net periodic pension cost. See Note 10 – “Employee Benefit Plans” for additional details.