Investments (Fair Value and Losses by Investment Category and Length of Time in a Loss Position) (Details) - Fixed maturity securities - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 37,868	$ 10,644
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	3,021	2,640
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	643	171
Debt Securities, Available-for-sale, Unrealized Loss Position	40,889	13,284
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	5,119	347
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,476	176
Non-investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,494	599
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	237	185
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	77	67
Debt Securities, Available-for-sale, Unrealized Loss Position	1,731	784
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	254	87
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	177	20
Investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	36,374	10,045
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,784	2,455
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	566	104
Debt Securities, Available-for-sale, Unrealized Loss Position	39,158	12,500
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	4,865	260
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,299	156
Corporate Debt Securities [Member] | Non-investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,234	463
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	103	97
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	25	44
Debt Securities, Available-for-sale, Unrealized Loss Position	1,337	560
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	162	57
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	137	13
Corporate Debt Securities [Member] | Investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	25,035	4,135
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,124	946
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	327	51
Debt Securities, Available-for-sale, Unrealized Loss Position	26,159	5,081
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	3,497	137
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3,170	86
Canadian and Canadian provincial governments | Investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	359	20
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	13	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	6	0
Debt Securities, Available-for-sale, Unrealized Loss Position	372	20
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	35	1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	29	1
Residential mortgage-backed securities | Investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	631	132
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	122	102
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	23	4
Debt Securities, Available-for-sale, Unrealized Loss Position	753	234
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	62	7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	39	3
Asset-backed securities | Non-investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	61	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	8	13
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2	13
Debt Securities, Available-for-sale, Unrealized Loss Position	69	13
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	11	13
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	9	0
Asset-backed securities | Investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,850	1,747
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	640	589
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	45	6
Debt Securities, Available-for-sale, Unrealized Loss Position	3,490	2,336
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	289	28
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	244	22
Commercial mortgage-backed securities | Non-investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	29	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	11	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1	0
Debt Securities, Available-for-sale, Unrealized Loss Position	40	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	4	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3	0
Commercial mortgage-backed securities | Investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,523	152
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	39	35
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	4	2
Debt Securities, Available-for-sale, Unrealized Loss Position	1,562	187
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	115	4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	111	2
US Government Agencies Debt Securities [Member] | Investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	839	1,513
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	24	31
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	9	2
Debt Securities, Available-for-sale, Unrealized Loss Position	863	1,544
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	146	8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	137	6
US States and Political Subdivisions Debt Securities [Member] | Investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	789	109
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	27	28
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	7	2
Debt Securities, Available-for-sale, Unrealized Loss Position	816	137
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	107	5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	100	3
Debt Security, Government, Non-US [Member] | Non-investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	170	136
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	115	75
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	49	10
Debt Securities, Available-for-sale, Unrealized Loss Position	285	211
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	77	17
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	28	7
Debt Security, Government, Non-US [Member] | Investment grade securities
Estimated Fair Values And Gross Unrealized Losses, OTTI Impairment Losses Reported In AOCI [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	4,348	2,237
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	795	724
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	145	37
Debt Securities, Available-for-sale, Unrealized Loss Position	5,143	2,961
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	614	70
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 469	$ 33