Segment Information (Total Assets of Reportable Segments) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 54,832,498	$ 50,383,152
Americas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	31,977,911	29,960,387
CANADA
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	3,904,326	3,631,887
EMEA [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	6,831,383	6,920,296
Asia Pacific [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	4,759,120	3,970,058
Corporate and Other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	7,359,758	5,900,524
Life Insurance Product Line [Member] | Americas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	17,883,476	16,554,509
Life Insurance Product Line [Member] | CANADA
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	3,820,039	3,604,344
Life Insurance Product Line [Member] | EMEA [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,703,577	2,757,593
Life Insurance Product Line [Member] | Asia Pacific [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	4,010,298	3,227,530
Nontraditional Long-Duration Contracts [Member] | Americas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	14,094,435	13,405,878
Nontraditional Long-Duration Contracts [Member] | CANADA
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	84,287	27,543
Nontraditional Long-Duration Contracts [Member] | EMEA [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	4,127,806	4,162,703
Nontraditional Long-Duration Contracts [Member] | Asia Pacific [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 748,822	$ 742,528