Segment Information (Total Assets of Reportable Segments) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 52,186,624	$ 50,383,152
Americas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	31,529,170	29,960,387
CANADA
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	3,704,393	3,631,887
EMEA [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	6,961,564	6,920,296
Asia Pacific [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	4,314,780	3,970,058
Corporate and Other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	5,676,717	5,900,524
Life Insurance Product Line [Member] | Americas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	17,622,125	16,554,509
Life Insurance Product Line [Member] | CANADA
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	3,673,055	3,604,344
Life Insurance Product Line [Member] | EMEA [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,651,864	2,757,593
Life Insurance Product Line [Member] | Asia Pacific [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	3,552,912	3,227,530
Nontraditional Long-Duration Contracts [Member] | Americas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	13,907,045	13,405,878
Nontraditional Long-Duration Contracts [Member] | CANADA
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	31,338	27,543
Nontraditional Long-Duration Contracts [Member] | EMEA [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	4,309,700	4,162,703
Nontraditional Long-Duration Contracts [Member] | Asia Pacific [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 761,868	$ 742,528