Fair Value of Assets and Liabilities (Balances of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2021		Dec. 31, 2020
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	$ 60,749		$ 56,735
Equity Method Investments, Fair Value Disclosure	151		132
Fair Value Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives	104		58
Funds Held Under Reinsurance Agreements, Asset Fair Value Disclosure	83		56
Cash and Cash Equivalents, Fair Value Disclosure	1,138		1,478
Fair Value Measured On Recurring Basis Short Term Investments	64		197
Derivative Assets (Liabilities), at Fair Value, Net	175	[1]	140
Investments, Fair Value Disclosure	227	[1]	429
Assets, Fair Value Disclosure	62,516		59,085
Liabilities, Fair Value Disclosure [Abstract]
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	855		907
Funds Held under Reinsurance Agreements, Liability	(61)		0
Other Liabilities, Fair Value Disclosure	39		49
Financial Liabilities Fair Value Disclosure	833		956
Fair Value, Net Asset (Liability)	581
Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,993		1,312
Equity Method Investments, Fair Value Disclosure	101		79
Fair Value Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives	0		0
Funds Held Under Reinsurance Agreements, Asset Fair Value Disclosure	0		0
Cash and Cash Equivalents, Fair Value Disclosure	1,138		1,478
Fair Value Measured On Recurring Basis Short Term Investments	0		32
Derivative Assets (Liabilities), at Fair Value, Net	0	[1]	0
Investments, Fair Value Disclosure	0	[1]	224
Assets, Fair Value Disclosure	3,232		3,125
Liabilities, Fair Value Disclosure [Abstract]
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	0		0
Funds Held under Reinsurance Agreements, Liability	0		0
Other Liabilities, Fair Value Disclosure	0
Financial Liabilities Fair Value Disclosure	0		0
Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	53,611		52,100
Equity Method Investments, Fair Value Disclosure	0		0
Fair Value Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives	0		0
Funds Held Under Reinsurance Agreements, Asset Fair Value Disclosure	0		0
Cash and Cash Equivalents, Fair Value Disclosure	0		0
Fair Value Measured On Recurring Basis Short Term Investments	36		150
Derivative Assets (Liabilities), at Fair Value, Net	175	[1]	140
Investments, Fair Value Disclosure	227	[1]	205
Assets, Fair Value Disclosure	53,874		52,455
Liabilities, Fair Value Disclosure [Abstract]
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	0		0
Funds Held under Reinsurance Agreements, Liability	0		0
Other Liabilities, Fair Value Disclosure	39
Financial Liabilities Fair Value Disclosure	39		49
Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	5,145		3,323
Equity Method Investments, Fair Value Disclosure	50		53
Fair Value Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives	104		58
Funds Held Under Reinsurance Agreements, Asset Fair Value Disclosure	83		56
Cash and Cash Equivalents, Fair Value Disclosure	0		0
Fair Value Measured On Recurring Basis Short Term Investments	28		15
Derivative Assets (Liabilities), at Fair Value, Net	0	[1]	0
Investments, Fair Value Disclosure	0	[1]	0
Assets, Fair Value Disclosure	5,410		3,505
Liabilities, Fair Value Disclosure [Abstract]
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	855		907
Funds Held under Reinsurance Agreements, Liability	(61)		0
Other Liabilities, Fair Value Disclosure	0
Financial Liabilities Fair Value Disclosure	794		907
Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure			0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure			49
Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure			0
Fair Value Option Contractholder Directed Unit Linked Investments [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	52	[1]	289
Fair Value Option Contractholder Directed Unit Linked Investments [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	[1]	224
Fair Value Option Contractholder Directed Unit Linked Investments [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	52	[1]	65
Fair Value Option Contractholder Directed Unit Linked Investments [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	[1]	0
Corporate Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	38,103		36,208
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0		0
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	34,215		33,179
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	3,888		3,029
Canadian Provincial Governments [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	4,944		5,140
Canadian Provincial Governments [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0		0
Canadian Provincial Governments [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	4,944		5,140
Canadian Provincial Governments [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0		0
Residential Mortgage Backed Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,050		1,817
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0		0
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,049		1,814
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1		3
Asset-backed Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	4,005		3,092
Assets, Fair Value Disclosure	205		87
Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0		0
Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	2,908		2,896
Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,097		196
Commercial Mortgage Backed Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,849		1,868
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0		0
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,768		1,813
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	81		55
US Treasury and Government [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	2,105		1,437
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,993		1,312
US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	100		111
US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	12		14
US States and Political Subdivisions Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,323		1,390
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0		0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,290		1,381
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	33		9
Debt Security, Government, Non-US [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	7,370		5,783
Debt Security, Government, Non-US [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0		0
Debt Security, Government, Non-US [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	7,337		5,766
Debt Security, Government, Non-US [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	$ 33		$ 17

[1] 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