Investments (Investments in Fixed Maturity and Equity Securities Available-for-Sale by Sector) (Details) - USD ($) $ in Millions	Jun. 30, 2023		Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	$ 62,185		$ 59,663
Fixed maturity securities, available-for-sale	56,236	[1]	52,901	[2]
Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	62,185		59,663
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	728		594
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	6,602		7,319
Fixed maturity securities, available-for-sale	$ 56,236		$ 52,901
% of Total	100.00%		100.00%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 75		$ 37
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	40,751		38,963
Fixed maturity securities, available-for-sale	$ 36,178	[1]	$ 33,969	[2]
% of Total	100.00%		100.00%
Corporate Debt Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	$ 40,751		$ 38,963
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	252		168
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4,763		5,135
Fixed maturity securities, available-for-sale	$ 36,178		$ 33,969
% of Total	64.30%		64.20%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 62		$ 27
Canadian and Canadian provincial governments
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available-for-sale	3,752	[1]	3,626	[2]
Canadian and Canadian provincial governments | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	3,395		3,311
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	404		381
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	47		66
Fixed maturity securities, available-for-sale	$ 3,752		$ 3,626
% of Total	6.70%		6.90%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available-for-sale	1,037	[1]	941	[2]
Residential mortgage-backed securities | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	1,145		1,054
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	3		1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	111		114
Fixed maturity securities, available-for-sale	$ 1,037		$ 941
% of Total	1.80%		1.80%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available-for-sale	4,165	[1]	3,878	[2]
Asset-backed Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	4,510		4,324
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	15		4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	348		440
Fixed maturity securities, available-for-sale	$ 4,165		$ 3,878
% of Total	7.40%		7.30%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 12		$ 10
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available-for-sale	1,699	[1]	1,623	[2]
Commercial Mortgage Backed Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	1,932		1,835
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	2		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	234		212
Fixed maturity securities, available-for-sale	$ 1,699		$ 1,623
% of Total	3.10%		3.10%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 1		$ 0
US Treasury and Government [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available-for-sale	1,366	[1]	1,482	[2]
US Treasury and Government [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	1,573		1,690
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1		4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	208		212
Fixed maturity securities, available-for-sale	$ 1,366		$ 1,482
% of Total	2.40%		2.80%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available-for-sale	1,109	[1]	1,119	[2]
US States and Political Subdivisions Debt Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	1,247		1,282
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	7		10
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	145		173
Fixed maturity securities, available-for-sale	$ 1,109		$ 1,119
% of Total	2.00%		2.10%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
Debt Security, Government, Non-US [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available-for-sale	3,884	[1]	3,704	[2]
Debt Security, Government, Non-US [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	4,317		4,171
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	34		22
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	467		489
Fixed maturity securities, available-for-sale	$ 3,884		$ 3,704
% of Total	6.90%		7.00%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
JAPAN | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	3,315		3,033
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	10		4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	279		478
Fixed maturity securities, available-for-sale	$ 3,046		$ 2,559
% of Total	5.40%		4.80%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0

[1] Excludes limited partnerships that are measured at estimated fair value using the NAV per share (or its equivalent) as a practical expedient. As of June 30, 2023, the fair value of such investments was $768 million.

[2] Excludes limited partnerships that are measured at estimated fair value using the NAV per share (or its equivalent) as a practical expedient. As of December 31, 2022, the fair value of such investments was $683 million