Investments (Investments in Fixed Maturity and Equity Securities Available-for-Sale by Sector) (Details) - USD ($) $ in Millions	Jun. 30, 2024		Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	$ 76,161		$ 64,977
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	964		1,125
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	6,523		5,560
Fixed maturity securities, available-for-sale	$ 70,491	[1]	$ 60,467	[2]
% of Total	100.00%		100.00%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 111		$ 75
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	50,053		42,014
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	516		554
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4,343		3,751
Fixed maturity securities, available-for-sale	$ 46,131	[1]	$ 38,755	[2]
% of Total	65.40%		64.10%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 95		$ 62
Canadian and Canadian provincial governments
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	4,520		3,477
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	331		473
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	71		33
Fixed maturity securities, available-for-sale	$ 4,780	[1]	$ 3,917	[2]
% of Total	6.80%		6.50%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	1,307		1,173
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	14		8
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109		102
Fixed maturity securities, available-for-sale	$ 1,212	[1]	$ 1,079	[2]
% of Total	1.70%		1.80%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	5,302		4,661
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	45		19
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	189		239
Fixed maturity securities, available-for-sale	$ 5,143	[1]	$ 4,429	[2]
% of Total	7.30%		7.30%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 15		$ 12
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	2,242		1,969
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	19		7
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	140		202
Fixed maturity securities, available-for-sale	$ 2,120	[1]	$ 1,773	[2]
% of Total	3.00%		2.90%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 1		$ 1
US Treasury and Government [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	1,681		2,725
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	3		9
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	256		214
Fixed maturity securities, available-for-sale	$ 1,428	[1]	$ 2,520	[2]
% of Total	2.00%		4.20%
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]
Available for Sale at Fair value - Amortized cost	1,188		1,236
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	4		7
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	150		129
Fixed maturity securities, available-for-sale	$ 1,042	[1]	$ 1,114	[2]
% of Total	1.60%		1.80%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
Debt Security, Government, Non-US [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	4,571		4,092
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	31		45
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	430		388
Fixed maturity securities, available-for-sale	$ 4,172	[1]	$ 3,749	[2]
% of Total	5.90%		6.20%
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
JAPAN
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	5,297		3,630
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1		3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	835		502
Fixed maturity securities, available-for-sale	$ 4,463		$ 3,131
% of Total	6.30%		5.20%
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, 2024, the fair value of such investments was $911 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, 2023, the fair value of such investments was $856 million