Fair Value of Assets and Liabilities Fair Value of Assets and Liabilities (Balances of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 31, 2022		Dec. 31, 2021
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	$ 57,922		$ 60,749
Equity Method Investments, Fair Value Disclosure	139		151
Funds withheld at interest embedded derivatives	(16)		(104)
Funds Held Under Reinsurance Agreements, Asset Fair Value Disclosure	75		83
Cash and cash equivalents	974		1,138
Short-term investments	268		64
Derivative Assets (Liabilities), at Fair Value, Net	134		175
Investments, Fair Value Disclosure	192	[1]	227	[2]
Assets, Fair Value Disclosure	59,554		62,516
Liabilities Fair Value Disclosure
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	793		855
Funds Held under Reinsurance Agreements, Liability	(147)		(61)
Other liabilities	(135)		(39)
Financial Liabilities Fair Value Disclosure	781		833
Fair Value, Net Asset (Liability)	609		581
Fair Value Option Contractholder Directed Unit Linked Investments [Member]
Assets Fair Value Disclosure
Investments, Fair Value Disclosure	58		52
Corporate Debt Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	36,380		38,103
Canadian and Canadian provincial governments
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	4,407		4,944
Residential mortgage-backed securities
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	966		1,050
Asset-backed Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	3,746		4,005
Assets, Fair Value Disclosure	183		205
Commercial Mortgage Backed Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	1,786		1,849
US Treasury and Government [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	1,525		2,105
US States and Political Subdivisions Debt Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	1,209		1,323
Debt Security, Government, Non-US [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	7,903		7,370
Fair Value Inputs Level 1 Member
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	1,415		1,993
Equity Method Investments, Fair Value Disclosure	91		101
Funds withheld at interest embedded derivatives	0		0
Funds Held Under Reinsurance Agreements, Asset Fair Value Disclosure	0		0
Cash and cash equivalents	974		1,138
Short-term investments	177		0
Derivative Assets (Liabilities), at Fair Value, Net	0		0
Investments, Fair Value Disclosure	0	[1]	0	[2]
Assets, Fair Value Disclosure	2,657		3,232
Liabilities Fair Value Disclosure
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	0		0
Funds Held under Reinsurance Agreements, Liability	0		0
Other liabilities	0		0
Financial Liabilities Fair Value Disclosure	0		0
Fair Value Inputs Level 1 Member | Fair Value Option Contractholder Directed Unit Linked Investments [Member]
Assets Fair Value Disclosure
Investments, Fair Value Disclosure	0		0
Fair Value Inputs Level 1 Member | Corporate Debt Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	0		0
Fair Value Inputs Level 1 Member | Canadian and Canadian provincial governments
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	0		0
Fair Value Inputs Level 1 Member | Residential mortgage-backed securities
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	0		0
Fair Value Inputs Level 1 Member | Asset-backed Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	0		0
Fair Value Inputs Level 1 Member | Commercial Mortgage Backed Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	0		0
Fair Value Inputs Level 1 Member | US Treasury and Government [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	1,415		1,993
Fair Value Inputs Level 1 Member | US States and Political Subdivisions Debt Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	0		0
Fair Value Inputs Level 1 Member | Debt Security, Government, Non-US [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	0		0
Fair Value Inputs Level 2 Member
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	51,267		53,611
Equity Method Investments, Fair Value Disclosure	0		0
Funds withheld at interest embedded derivatives	0		0
Funds Held Under Reinsurance Agreements, Asset Fair Value Disclosure	0		0
Cash and cash equivalents	0		0
Short-term investments	43		36
Derivative Assets (Liabilities), at Fair Value, Net	134		175
Investments, Fair Value Disclosure	192	[1]	227	[2]
Assets, Fair Value Disclosure	51,502		53,874
Liabilities Fair Value Disclosure
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	0		0
Funds Held under Reinsurance Agreements, Liability	0		0
Other liabilities	(135)		(39)
Financial Liabilities Fair Value Disclosure	135		39
Fair Value Inputs Level 2 Member | Fair Value Option Contractholder Directed Unit Linked Investments [Member]
Assets Fair Value Disclosure
Investments, Fair Value Disclosure	58		52
Fair Value Inputs Level 2 Member | Corporate Debt Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	32,334		34,215
Fair Value Inputs Level 2 Member | Canadian and Canadian provincial governments
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	4,407		4,944
Fair Value Inputs Level 2 Member | Residential mortgage-backed securities
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	959		1,049
Fair Value Inputs Level 2 Member | Asset-backed Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	2,710		2,908
Fair Value Inputs Level 2 Member | Commercial Mortgage Backed Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	1,708		1,768
Fair Value Inputs Level 2 Member | US Treasury and Government [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	100		100
Fair Value Inputs Level 2 Member | US States and Political Subdivisions Debt Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	1,175		1,290
Fair Value Inputs Level 2 Member | Debt Security, Government, Non-US [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	7,874		7,337
Fair Value Inputs Level 3 Member
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	5,240		5,145
Equity Method Investments, Fair Value Disclosure	48		50
Funds withheld at interest embedded derivatives	(16)		(104)
Funds Held Under Reinsurance Agreements, Asset Fair Value Disclosure	75		83
Cash and cash equivalents	0		0
Short-term investments	48		28
Derivative Assets (Liabilities), at Fair Value, Net	0		0
Investments, Fair Value Disclosure	0	[1]	0	[2]
Assets, Fair Value Disclosure	5,395		5,410
Liabilities Fair Value Disclosure
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	793		855
Funds Held under Reinsurance Agreements, Liability	(147)		(61)
Other liabilities	0		0
Financial Liabilities Fair Value Disclosure	646		794
Fair Value Inputs Level 3 Member | Fair Value Option Contractholder Directed Unit Linked Investments [Member]
Assets Fair Value Disclosure
Investments, Fair Value Disclosure	0		0
Fair Value Inputs Level 3 Member | Corporate Debt Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	4,046		3,888
Fair Value Inputs Level 3 Member | Canadian and Canadian provincial governments
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	0		0
Fair Value Inputs Level 3 Member | Residential mortgage-backed securities
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	7		1
Fair Value Inputs Level 3 Member | Asset-backed Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	1,036		1,097
Fair Value Inputs Level 3 Member | Commercial Mortgage Backed Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	78		81
Fair Value Inputs Level 3 Member | US Treasury and Government [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	10		12
Fair Value Inputs Level 3 Member | US States and Political Subdivisions Debt Securities [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	34		33
Fair Value Inputs Level 3 Member | Debt Security, Government, Non-US [Member]
Assets Fair Value Disclosure
Fixed maturity securities, available-for-sale	$ 29		$ 33

[1] Other invested assets included in the fair value hierarchy exclude limited partnership interests that are measured at estimated fair value using the net asset value (“NAV”) per share (or its equivalent) as a practical expedient. As of March 31, 2022, the fair value of such investments was $609 million.

[2] Other invested assets included in the fair value hierarchy exclude limited partnership interests 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