Segment Information (Reconciliation of Depreciation and Amortization from Segment to Consolidated) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	$ 589	$ 609	$ 574
Americas [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	381	434	368
Canada Segment Reporting Information [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	24	20	22
EMEA [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	47	57	45
Asia Pacific [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	114	76	117
Corporate And Other Segment Reporting Information [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	23	22	22
Life Insurance Product Line [Member] | Americas [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	291	291	273
Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	24	20	22
Life Insurance Product Line [Member] | EMEA [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	46	56	45
Life Insurance Product Line [Member] | Asia Pacific [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	94	60	115
Insurance, Other [Member] | Americas [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	90	143	95
Insurance, Other [Member] | Canada Segment Reporting Information [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	0	0	0
Insurance, Other [Member] | EMEA [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	1	1	0
Insurance, Other [Member] | Asia Pacific [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	$ 20	$ 16	$ 2