Equity (Tables)

12 Months Ended

Dec. 31, 2015

Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]

Schedule of Stock by Class [Table Text Block]

The changes in number of common stock shares, issued, held in treasury and outstanding are as follows for the periods indicated:

	Issued	Held In Treasury		Outstanding
Balance, December 31, 2012	79,137,758	5,210,427		73,927,331
Common Stock acquired	—	4,151,312		(4,151,312	)
Stock-based compensation (1)	—	(992,199	)	992,199
Balance, December 31, 2013	79,137,758	8,369,540		70,768,218
Common Stock acquired	—	2,530,608		(2,530,608	)
Stock-based compensation (1)	—	(535,351	)	535,351
Balance, December 31, 2014	79,137,758	10,364,797		68,772,961
Common Stock acquired	—	4,145,440		(4,145,440	)
Stock-based compensation (1)	—	(577,005	)	577,005
Balance, December 31, 2015	79,137,758	13,933,232		65,204,526

(1) Represents net shares issued from treasury pursuant to the Company's stock-based compensation programs.

Schedule of Comprehensive Income (Loss) [Table Text Block]

The following table presents the components of the Company’s other comprehensive income (loss) for the years ended December 31, 2015, 2014 and 2013 (dollars in thousands):

For the year ended December 31, 2015:

	Before-Tax Amount			Tax (Expense) Benefit			After-Tax Amount
Foreign currency translation adjustments:
Change arising during year	$	(342,539	)	$	17,129		$	(325,410	)
Foreign currency swap	96,019			(33,607		)	62,412
Net foreign currency translation adjustments	(246,520		)	(16,478		)	(262,998		)
Unrealized losses on investments:(1)
Unrealized net holding losses arising during the year	(1,084,732		)	359,407			(725,325		)
Less: Reclassification adjustment for net losses realized in net income	(55,767		)	19,518			(36,249		)
Net unrealized losses	(1,028,965		)	339,889			(689,076		)
Unrealized pension and postretirement benefits:
Net prior service cost arising during the year	337			(107		)	230
Net loss arising during the period	4,618			(1,619		)	2,999
Unrealized pension and postretirement benefits, net	4,955			(1,726		)	3,229
Other comprehensive income	$	(1,270,530	)	$	321,685		$	(948,845	)

For the year ended December 31, 2014:

	Before-Tax Amount			Tax (Expense) Benefit			After-Tax Amount
Foreign currency translation adjustments:
Change arising during year	$	(154,132	)	$	(4,835	)	$	(158,967	)
Foreign currency swap	51,894			(18,163		)	33,731
Net foreign currency translation adjustments	(102,238		)	(22,998		)	(125,236		)
Unrealized gains on investments:(1)
Unrealized net holding gains arising during the year	1,177,017			(357,024		)	819,993
Less: Reclassification adjustment for net gains realized in net income	26,405			(9,242		)	17,163
Net unrealized gains	1,150,612			(347,782		)	802,830
Change in unrealized OTTI on fixed maturity securities	2,612			(914		)	1,698
Unrealized pension and postretirement benefits:
Net prior service cost arising during the year	485			(159		)	326
Net gain arising during the period	(43,025		)	14,929			(28,096		)
Unrealized pension and postretirement benefits, net	(42,540		)	14,770			(27,770		)
Other comprehensive income (loss)	$	1,008,446		$	(356,924	)	$	651,522
For the year ended December 31, 2013:
	Before-Tax Amount			Tax (Expense) Benefit			After-Tax Amount
Foreign currency translation adjustments:
Change arising during year	$	(88,409	)	$	1,791		$	(86,618	)
Foreign currency swap	40,347			(14,121		)	26,226
Net foreign currency translation adjustments	(48,062		)	(12,330		)	(60,392		)
Unrealized losses on investments:(1)
Unrealized net holding losses arising during the year	(1,519,967		)	465,740			(1,054,227		)
Less: Reclassification adjustment for net gains realized in net income	9,355			(3,274		)	6,081
Net unrealized losses	(1,529,322		)	469,014			(1,060,308		)
Change in unrealized OTTI on fixed maturity securities	4,456			(1,560		)	2,896
Unrealized pension and postretirement benefits:
Net prior service cost arising during the year	525			(171		)	354
Net loss arising during the period	21,624			(7,469		)	14,155
Unrealized pension and postretirement benefits, net	22,149			(7,640		)	14,509
Other comprehensive income	$	(1,550,779	)	$	447,484		$	(1,103,295	)

(1) Includes cash flow hedges. See Note 5 for additional information on cash flow hedges.

Components Of Accumulated Other Comprehensive Income [Table Text Block]

A summary of the components of net unrealized appreciation (depreciation) of balances carried at fair value is as follows (dollars in thousands):

For the years ended December 31,	2015			2014			2013
Change in net unrealized appreciation (depreciation) on:
Fixed maturity securities available-for-sale	$	(1,055,458	)	$	1,171,996		$	(1,528,773	)
Other investments(1)	8,983			(14,292		)	(12,274		)
Effect on unrealized appreciation on:
Deferred policy acquisition costs	17,510			(4,480		)	16,181
Net unrealized appreciation (depreciation)	$	(1,028,965	)	$	1,153,224		$	(1,524,866	)

(1) Includes cash flow hedges. See Note 5 for additional information on cash flow hedges.

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

The balance of and changes in each component of AOCI were as follows (dollars in thousands):

	Accumulated Currency Translation Adjustments			Unrealized Appreciation (Depreciation) of Investments (1)			Pension and Postretirement Benefits			Accumulated Other Comprehensive Income (Loss)
Balance, December 31, 2012	$	267,475		$	1,877,657		$	(36,230	)	$	2,108,902
OCI before reclassifications	(48,062		)	(1,530,680		)	17,638			(1,561,104		)
Amounts reclassified from AOCI	—			5,814			4,511			10,325
Deferred income tax benefit (expense)	(12,330		)	467,454			(7,640		)	447,484
Balance, December 31, 2013	207,083			820,245			(21,721		)	1,005,607
OCI before reclassifications	(102,238		)	1,185,321			(45,688		)	1,037,395
Amounts reclassified from AOCI	—			(32,097		)	3,148			(28,949		)
Deferred income tax benefit (expense)	(22,998		)	(348,696		)	14,770			(356,924		)
Balance, December 31, 2014	81,847			1,624,773			(49,491		)	1,657,129
OCI before reclassifications	(246,520		)	(1,101,760		)	(1,248		)	(1,349,528		)
Amounts reclassified from AOCI	—			72,795			6,203			78,998
Deferred income tax benefit (expense)	(16,478		)	339,889			(1,726		)	321,685
Balance, December 31, 2015	$	(181,151	)	$	935,697		$	(46,262	)	$	708,284

(1) Includes cash flow hedges. See Note 5 for additional information on cash flow hedges.

Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]

The following table presents the amounts of AOCI reclassifications for the years ended December 31, 2015 and 2014 (dollars in thousands):

	Amount Reclassified from AOCI
Details about AOCI Components	2015			2014			Affected Line Item in  Statement of Income
Net unrealized investment gains (losses):
Net unrealized gains and losses on available-for-sale securities	$	(55,767	)	$	26,405		Investment related gains (losses), net
Cash flow hedges - Interest rate swaps	569			1,212			(1)
Cash flow hedges - Forward bond purchase commitments	(87		)	—			(1)
Deferred policy acquisition costs attributed to unrealized gains and losses	(17,510		)	4,480			(2)
Total	(72,795		)	32,097
Provision for income taxes	28,109			(7,319		)
Net unrealized gains (losses), net of tax	$	(44,686	)	$	24,778
Amortization of defined benefit plan items:
Prior service cost	$	(309	)	$	(333	)	(3)
Actuarial gains/(losses)	(5,894		)	(2,815		)	(3)
Total	(6,203		)	(3,148		)
Provision for income taxes	2,171			1,082
Amortization of defined benefit plans, net of tax	$	(4,032	)	$	(2,066	)
Total reclassifications for the period	$	(48,718	)	$	22,712

(1) See Note 5 for information on cash flow hedges.

(2) See Note 8 for information on deferred policy acquisition costs.

(3) See Note 10 for information on employee benefit plans.