Investments (Investments in Fixed Maturity and Equity Securities Available-for-Sale by Sector) (Details) - USD ($) $ in Millions	Mar. 31, 2023		Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	$ 61,494		$ 59,663
Fixed maturity securities, available-for-sale	56,085	[1]	52,901	[2]
Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	61,494		59,663
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	775		594
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	6,105		7,319
Fixed maturity securities, available-for-sale	$ 56,085		$ 52,901
% of Total	100.00%		100.00%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 79		$ 37
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	39,621		38,963
Fixed maturity securities, available-for-sale	$ 35,477	[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	$ 39,621		$ 38,963
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	255		168
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4,330		5,135
Fixed maturity securities, available-for-sale	$ 35,477		$ 33,969
% of Total	63.30%		64.20%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 69		$ 27
Canadian and Canadian provincial governments
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available-for-sale	3,755	[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	3,345		3,311
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	455		381
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	45		66
Fixed maturity securities, available-for-sale	$ 3,755		$ 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	1,024	[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	1,120		1,054
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	2		1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	98		114
Fixed maturity securities, available-for-sale	$ 1,024		$ 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	4,103	[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	4,470		4,324
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	8		4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	365		440
Fixed maturity securities, available-for-sale	$ 4,103		$ 3,878
% of Total	7.30%		7.30%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 10		$ 10
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available-for-sale	1,670	[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	1,882		1,835
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	212		212
Fixed maturity securities, available-for-sale	$ 1,670		$ 1,623
% of Total	3.00%		3.10%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
US Treasury and Government [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available-for-sale	1,745	[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	1,923		1,690
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	6		4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	184		212
Fixed maturity securities, available-for-sale	$ 1,745		$ 1,482
% of Total	3.10%		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	1,138	[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	1,261		1,282
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	9		10
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	132		173
Fixed maturity securities, available-for-sale	$ 1,138		$ 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	3,730	[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	4,123		4,171
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	31		22
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	424		489
Fixed maturity securities, available-for-sale	$ 3,730		$ 3,704
% of Total	6.70%		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	3,749		3,033
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	9		4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	315		478
Fixed maturity securities, available-for-sale	$ 3,443		$ 2,559
% of Total	6.10%		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 March 31, 2023, the fair value of such investments was $726 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