Investments (Investments in Fixed Maturity and Equity Securities Available-for-Sale by Sector) (Details) - USD ($) $ in Millions	Dec. 31, 2022		Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Financing Receivable, Allowance for Credit Loss	$ 37		$ 31
Available for Sale at Fair value - Amortized cost	59,663		55,873
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	$ 52,901	[1]	$ 60,749	[2]
Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Percentage Of Total Available For Sale Securities	100.00%		100.00%
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 7,319		$ 349
Available for Sale at Fair value - Amortized cost	59,663		55,873
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	52,901		60,749
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	594		5,256
Debt Securities, Available-for-Sale, Allowance for Credit Loss	37		31
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	38,963		35,239
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	$ 33,969	[1]	$ 38,103	[2]
Corporate Debt Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Percentage Of Total Available For Sale Securities	64.20%		62.80%
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 5,135		$ 194
Available for Sale at Fair value - Amortized cost	38,963		35,239
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	33,969		38,103
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	168		3,084
Debt Securities, Available-for-Sale, Allowance for Credit Loss	27		26
Canadian Provincial Governments [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	$ 3,626	[1]	$ 4,944	[2]
Canadian Provincial Governments [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Percentage Of Total Available For Sale Securities	6.90%		8.10%
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 66		$ 1
Available for Sale at Fair value - Amortized cost	3,311		3,339
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	3,626		4,944
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	381		1,606
Debt Securities, Available-for-Sale, Allowance for Credit Loss	0		0
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	$ 941	[1]	$ 1,050	[2]
Residential Mortgage Backed Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Percentage Of Total Available For Sale Securities	1.80%		1.70%
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 114		$ 7
Available for Sale at Fair value - Amortized cost	1,054		1,020
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	941		1,050
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1		37
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 at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	$ 3,878	[1]	$ 4,005	[2]
Asset-backed Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Percentage Of Total Available For Sale Securities	7.30%		6.60%
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 440		$ 41
Available for Sale at Fair value - Amortized cost	4,324		4,024
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	3,878		4,005
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	4		22
Debt Securities, Available-for-Sale, Allowance for Credit Loss	10		0
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	$ 1,623	[1]	$ 1,849	[2]
Commercial Mortgage Backed Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Percentage Of Total Available For Sale Securities	3.10%		3.00%
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 212		$ 6
Available for Sale at Fair value - Amortized cost	1,835		1,790
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	1,623		1,849
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0		66
Debt Securities, Available-for-Sale, Allowance for Credit Loss	0		1
US Treasury and Government [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	$ 1,482	[1]	$ 2,105	[2]
US Treasury and Government [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Percentage Of Total Available For Sale Securities	2.80%		3.50%
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 212		$ 8
Available for Sale at Fair value - Amortized cost	1,690		2,082
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	1,482		2,105
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	4		31
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 at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	$ 1,119	[1]	$ 1,323	[2]
US States and Political Subdivisions Debt Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Percentage Of Total Available For Sale Securities	2.10%		2.20%
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 173		$ 5
Available for Sale at Fair value - Amortized cost	1,282		1,191
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	1,119		1,323
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	10		137
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 at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	$ 6,263	[1]	$ 7,370	[2]
Debt Security, Government, Non-US [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Percentage Of Total Available For Sale Securities	11.80%		12.10%
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 967		$ 87
Available for Sale at Fair value - Amortized cost	7,204		7,188
Fixed maturity securities available-for-sale at fair value (amortized cost of $59,663 and $55,873; allowance for credit losses of $37 and $31)	6,263		7,370
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	26		273
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 4

[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 December 31, 2022, the fair value of such investments was $683 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, 2021, the fair value of such investments was $581 million.