Investments (Fair Value and Losses by Investment Category and Length of Time in a Loss Position) (Details) - Fixed maturity securities - USD ($) $ in Millions	Sep. 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	$ 37,134	$ 10,644
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5,378	2,640
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,444	171
Debt Securities, Available-for-sale, Unrealized Loss Position	42,512	13,284
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	7,776	347
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	6,332	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	1,405	599
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	367	185
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	134	67
Debt Securities, Available-for-sale, Unrealized Loss Position	1,772	784
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	295	87
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	161	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	35,729	10,045
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5,011	2,455
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,310	104
Debt Securities, Available-for-sale, Unrealized Loss Position	40,740	12,500
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	7,481	260
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	6,171	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	1,144	463
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	202	97
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	62	44
Debt Securities, Available-for-sale, Unrealized Loss Position	1,346	560
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	180	57
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	118	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	25,451	4,135
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,283	946
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	811	51
Debt Securities, Available-for-sale, Unrealized Loss Position	27,734	5,081
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	5,572	137
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,761	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	368	20
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	12	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	5	0
Debt Securities, Available-for-sale, Unrealized Loss Position	380	20
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	41	1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	36	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	678	132
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	128	102
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	36	4
Debt Securities, Available-for-sale, Unrealized Loss Position	806	234
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	105	7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	69	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	53	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	23	13
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	7	13
Debt Securities, Available-for-sale, Unrealized Loss Position	76	13
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	19	13
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	12	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	2,333	1,747
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,054	589
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	121	6
Debt Securities, Available-for-sale, Unrealized Loss Position	3,387	2,336
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	417	28
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	296	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	22	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	18	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3	0
Debt Securities, Available-for-sale, Unrealized Loss Position	40	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	6	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	1,461	152
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	83	35
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	17	2
Debt Securities, Available-for-sale, Unrealized Loss Position	1,544	187
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	166	4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	149	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	721	1,513
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	116	31
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	14	2
Debt Securities, Available-for-sale, Unrealized Loss Position	837	1,544
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	204	8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	190	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	883	109
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	44	28
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	16	2
Debt Securities, Available-for-sale, Unrealized Loss Position	927	137
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	177	5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	161	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	186	136
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	124	75
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	62	10
Debt Securities, Available-for-sale, Unrealized Loss Position	310	211
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	90	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	3,834	2,237
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,291	724
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	290	37
Debt Securities, Available-for-sale, Unrealized Loss Position	5,125	2,961
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	799	70
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 509	$ 33