Accumulated Other Comprehensive Income (Schedule of Reclassifications out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015	Jun. 30, 2014
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Investment related gains (losses), net	$ (12,041)		$ 119,397		$ (1,931)	$ 204,271
Investment income	450,539		410,607		877,430	814,982
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	2,038				1,258
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	213,790		300,535		397,915	499,975
Income Tax Expense (Benefit)	(83,399)		(102,239)		(142,410)	(165,015)
Net income	130,391		198,296		255,505	334,960
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	(440)		31,833		6,192	37,661
Income Tax Expense (Benefit)	(245)		(11,059)		(537)	(12,963)
Net income	(685)		20,774		5,655	24,698
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	1,829		27,142		4,908	28,331
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	1,495		0		655	0
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	543		321		603	539
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	(4,307)	[1]	4,370	[1]	(26)	8,791	[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	(1,178)		(678)		(1,965)	(1,570)
Income Tax Expense (Benefit)	413		238		688	550
Net income	(765)		(440)		(1,277)	(1,020)
Amounts Reclassified From AOCI [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net income	(1,450)		20,334		4,378	23,678
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	(80)	[2]	(216)	[2]	(163)	(218)	[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)	$ (1,098)	[2]	$ (462)	[2]	$ 1,802	$ (1,352)	[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 2014 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.