Accumulated Other Comprehensive Income (Schedule of Reclassifications out of AOCI) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Investment related gains (losses), net	$ 22,564		$ (76,133)		$ 226,835		$ 76,792
Investment income	447,106		369,366		1,262,088		1,238,731
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	231,815		201,695		731,790		405,764
Tax (expense) benefit	(73,819)		(63,740)		(238,834)		(131,886)
Net income	157,996		137,955		492,956		273,878
Unrealized Appreciation Depreciation Of Investments [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	(1,626)		(13,047)		36,035		(3,515)
Tax (expense) benefit	588		5,009		(12,374)		1,988
Net income	(1,038)		(8,038)		23,661		(1,527)
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	2,218		(12,736)		30,549		11,122
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	393		291		932		796
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	(4,237)	[1]	(602)	[1]	4,554	[1]	(15,433)	[1]
Amortization Of Unrealized Pension And Postretirement Benefits [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	(1,064)		(1,239)		(2,634)		(3,537)
Tax (expense) benefit	372		434		922		1,238
Net income	(692)		(805)		(1,712)		(2,299)
Amounts Reclassified From AOCI [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net income	(1,730)		(8,843)		21,949		(3,826)
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	(214)	[2]	(152)	[2]	(432)	[2]	(459)	[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)	$ (850)	[2]	$ (1,087)	[2]	$ (2,202)	[2]	$ (3,078)	[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.