Segment Information (Reconciliation of Revenue from Segments to Consolidated) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 3,785	$ 3,628	$ 3,467	$ 3,420	$ 3,279	$ 3,227	$ 3,196	$ 3,174	$ 14,300	$ 12,876	$ 12,516
Americas [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									7,779	7,203	7,251
Canada Segment Reporting Information [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,385	1,273	1,152
EMEA [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,970	1,845	1,673
Asia Pacific [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									2,909	2,471	2,284
Corporate and Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									257	84	156
Life Insurance Product Line [Member] | Americas [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									6,500	6,296	6,100
Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,286	1,224	1,103
Life Insurance Product Line [Member] | EMEA [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,520	1,495	1,362
Life Insurance Product Line [Member] | Asia Pacific [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									2,681	2,417	2,210
Insurance, Other [Member] | Americas [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,279	907	1,151
Insurance, Other [Member] | Canada Segment Reporting Information [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									99	49	49
Insurance, Other [Member] | EMEA [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									450	350	311
Insurance, Other [Member] | Asia Pacific [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									$ 228	$ 54	$ 74