Policy Claims and Benefits (Claims Development) (Details) - Life Insurance Product Line [Member] - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019	[1]	Dec. 31, 2018	[1]	Dec. 31, 2017	[1]	Dec. 31, 2016	[1]	Dec. 31, 2015	[1]	Dec. 31, 2014	[1]	Dec. 31, 2013	[1]	Dec. 31, 2012	[1]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net		$ 1,594
Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		1,809
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented		90
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		2,525
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net		806
Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		3,303
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented		131
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	3,960
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net		788
Short-duration Insurance Contracts, Accident Year 2012 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		318	$ 310		$ 300		$ 284		$ 266		$ 243		$ 202		$ 148		$ 54
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		345	343		338		332		321		313		309		305		227
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		5
Short-duration Insurance Contracts, Accident Year 2012 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		275	272		268		264		258		252		244		222		109
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		296	297		297		298		299		298		297		309		$ 323
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		0
Short-duration Insurance Contracts, Accident Year 2013 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		332	322		309		285		258		229		157		54
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		359	361		358		343		329		332		342		320
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		7
Short-duration Insurance Contracts, Accident Year 2013 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		305	302		297		292		286		277		249		114
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		335	337		336		336		337		339		333		$ 349
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		0
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		276	265		250		225		194		148		38
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		313	312		310		296		290		328		302
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		9
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		368	364		356		349		337		305		129
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		399	399		396		397		396		411		$ 408
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		0
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		255	242		221		183		129		53
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		292	291		292		273		281		304
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		14
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		437	431		422		407		361		146
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		463	462		462		465		461		$ 460
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		0
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		182	167		145		107		42
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		240	240		232		225		248
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		15
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		460	451		437		393		185
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		497	497		501		500		$ 501
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		0
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		149	126		95		39
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		237	234		234		232
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		21
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		462	448		403		190
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		504	509		514		$ 485
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		3
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		160	116		35
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		290	295		277
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		50
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		465	415		183
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		524	538		$ 538
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		8
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		111	42
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		286	277
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		82
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		372	180
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		473	$ 491
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		30
Short-Duration Insurance Contract, Accident Year 2020 | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		26
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		163
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		84
Short-Duration Insurance Contract, Accident Year 2020 | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net		159
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net		469
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		$ 197

[1] 2012-2019 Unaudited.