Supplementary Insurance Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplementary Insurance Information, by Segment [Line Items]
Supplementary Insurance Information, Deferred Policy Acquisition Costs		$ 3,392,437	$ 3,342,575
Supplementary Insurance Information, Liability for Future Policy Benefits, Losses, Claims and Loss Expense Reserves		33,276,124	27,068,134
Supplementary Insurance Information, Other Policy Claims and Benefits Payable		4,094,640	3,824,069
Supplementary Insurance Information, Premium Revenue		8,570,741	8,669,854	$ 8,254,027
Supplementary Insurance Information, Net Investment Income		1,734,495	1,713,691	1,699,865
Supplementary Insurance Information, Benefits, Claims, Losses and Settlement Expense		7,826,346	7,857,672	7,780,846
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	[1]	229,876	979,365	912,803
Supplementary Insurance Information, Other Operating Expense		1,617,161	1,058,624	989,450
US Traditional Segment Reporting Information [Member]
Supplementary Insurance Information, by Segment [Line Items]
Supplementary Insurance Information, Deferred Policy Acquisition Costs		1,807,407	1,688,827
Supplementary Insurance Information, Liability for Future Policy Benefits, Losses, Claims and Loss Expense Reserves		10,593,424	8,440,882
Supplementary Insurance Information, Other Policy Claims and Benefits Payable		1,681,130	1,459,444
Supplementary Insurance Information, Premium Revenue		4,806,706	4,725,505	4,563,490
Supplementary Insurance Information, Net Investment Income		636,779	552,805	543,824
Supplementary Insurance Information, Benefits, Claims, Losses and Settlement Expense		4,444,196	4,181,492	4,016,453
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	[1]	131,439	467,067	471,726
Supplementary Insurance Information, Other Operating Expense		653,620	283,064	250,175
US Non-Traditional Segment Reporting Information [Member]
Supplementary Insurance Information, by Segment [Line Items]
Supplementary Insurance Information, Deferred Policy Acquisition Costs		691,944	690,698
Supplementary Insurance Information, Liability for Future Policy Benefits, Losses, Claims and Loss Expense Reserves		12,882,145	10,915,471
Supplementary Insurance Information, Other Policy Claims and Benefits Payable		16,430	14,656
Supplementary Insurance Information, Premium Revenue		22,177	20,079	22,521
Supplementary Insurance Information, Net Investment Income		566,180	644,285	721,282
Supplementary Insurance Information, Benefits, Claims, Losses and Settlement Expense		310,464	402,387	443,393
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	[1]	40,416	203,605	185,396
Supplementary Insurance Information, Other Operating Expense		85,022	105,207	88,380
Canada Traditional Segment Reporting Information [Member]
Supplementary Insurance Information, by Segment [Line Items]
Supplementary Insurance Information, Deferred Policy Acquisition Costs		197,243	237,295
Supplementary Insurance Information, Liability for Future Policy Benefits, Losses, Claims and Loss Expense Reserves		2,498,385	2,825,938
Supplementary Insurance Information, Other Policy Claims and Benefits Payable		160,478	208,246
Supplementary Insurance Information, Premium Revenue		838,894	953,389	939,013
Supplementary Insurance Information, Net Investment Income		182,621	193,610	201,986
Supplementary Insurance Information, Benefits, Claims, Losses and Settlement Expense		670,477	784,470	737,028
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	[1]	11,299	190,164	178,566
Supplementary Insurance Information, Other Operating Expense		217,061	83,446	81,581
Canada Non-Traditional Segment Reporting Information [Member]
Supplementary Insurance Information, by Segment [Line Items]
Supplementary Insurance Information, Deferred Policy Acquisition Costs		0	0
Supplementary Insurance Information, Liability for Future Policy Benefits, Losses, Claims and Loss Expense Reserves		26,547	35,114
Supplementary Insurance Information, Other Policy Claims and Benefits Payable		2,829	1,497
Supplementary Insurance Information, Premium Revenue		37,969	21,192	23,298
Supplementary Insurance Information, Net Investment Income		1,436	2,595	2,865
Supplementary Insurance Information, Benefits, Claims, Losses and Settlement Expense		29,251	20,116	21,537
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	[1]	0	0	0
Supplementary Insurance Information, Other Operating Expense		1,881	1,969	1,988
EMEA Traditional Segment Reporting Information [Member]
Supplementary Insurance Information, by Segment [Line Items]
Supplementary Insurance Information, Deferred Policy Acquisition Costs		236,194	272,016
Supplementary Insurance Information, Liability for Future Policy Benefits, Losses, Claims and Loss Expense Reserves		1,104,771	1,052,702
Supplementary Insurance Information, Other Policy Claims and Benefits Payable		754,573	749,965
Supplementary Insurance Information, Premium Revenue		1,121,540	1,157,407	1,069,375
Supplementary Insurance Information, Net Investment Income		51,370	52,086	49,212
Supplementary Insurance Information, Benefits, Claims, Losses and Settlement Expense		979,225	1,013,331	956,424
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	[1]	39,164	43,549	40,780
Supplementary Insurance Information, Other Operating Expense		123,943	117,864	101,044
EMEA Non-Traditional Segment Reporting Information [Member]
Supplementary Insurance Information, by Segment [Line Items]
Supplementary Insurance Information, Deferred Policy Acquisition Costs		0	0
Supplementary Insurance Information, Liability for Future Policy Benefits, Losses, Claims and Loss Expense Reserves		3,994,702	1,919,644
Supplementary Insurance Information, Other Policy Claims and Benefits Payable		35,801	34,456
Supplementary Insurance Information, Premium Revenue		171,830	216,562	151,368
Supplementary Insurance Information, Net Investment Income		73,432	55,043	2,822
Supplementary Insurance Information, Benefits, Claims, Losses and Settlement Expense		161,917	204,110	116,537
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	[1]	0	0	0
Supplementary Insurance Information, Other Operating Expense		16,304	17,351	15,674
Asia Pacific Traditional Segment Reporting Information [Member]
Supplementary Insurance Information, by Segment [Line Items]
Supplementary Insurance Information, Deferred Policy Acquisition Costs		457,372	451,261
Supplementary Insurance Information, Liability for Future Policy Benefits, Losses, Claims and Loss Expense Reserves		1,115,987	1,073,476
Supplementary Insurance Information, Other Policy Claims and Benefits Payable		1,420,248	1,330,251
Supplementary Insurance Information, Premium Revenue		1,551,586	1,540,910	1,434,832
Supplementary Insurance Information, Net Investment Income		80,549	84,489	77,407
Supplementary Insurance Information, Benefits, Claims, Losses and Settlement Expense		1,208,984	1,208,611	1,430,140
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	[1]	7,373	74,571	36,116
Supplementary Insurance Information, Other Operating Expense		316,346	312,652	297,303
Asia Pacific Non-Traditional Segment Reporting Information [Member]
Supplementary Insurance Information, by Segment [Line Items]
Supplementary Insurance Information, Deferred Policy Acquisition Costs		2,277	2,478
Supplementary Insurance Information, Liability for Future Policy Benefits, Losses, Claims and Loss Expense Reserves		758,301	505,300
Supplementary Insurance Information, Other Policy Claims and Benefits Payable		14,634	13,999
Supplementary Insurance Information, Premium Revenue		19,474	34,030	50,373
Supplementary Insurance Information, Net Investment Income		18,678	17,972	16,923
Supplementary Insurance Information, Benefits, Claims, Losses and Settlement Expense		20,766	42,351	58,527
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	[1]	185	409	219
Supplementary Insurance Information, Other Operating Expense		16,011	15,829	14,986
Corporate And Other Segment Reporting Information [Member]
Supplementary Insurance Information, by Segment [Line Items]
Supplementary Insurance Information, Deferred Policy Acquisition Costs		0	0
Supplementary Insurance Information, Liability for Future Policy Benefits, Losses, Claims and Loss Expense Reserves		301,862	299,607
Supplementary Insurance Information, Other Policy Claims and Benefits Payable		8,517	11,555
Supplementary Insurance Information, Premium Revenue		565	780	(243)
Supplementary Insurance Information, Net Investment Income		123,450	110,806	83,544
Supplementary Insurance Information, Benefits, Claims, Losses and Settlement Expense		1,066	804	807
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	[1]	0	0	0
Supplementary Insurance Information, Other Operating Expense		$ 186,973	$ 121,242	$ 138,319

[1] During 2015, the Company enhanced its process to track certain DAC components in a more refined manner, See Note 8 - “Deferred Policy Acquisition Costs” in the Notes to Consolidated Financial Statements for additional information.