Impact of New Accounting Standard (DAC) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs			$ 4,617	$ 4,128
Accounting Standards Update 2018-12
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs				4,128	$ 3,860
Deferred Policy Acquisition Costs, Amortization Expense	$ (1,344)	$ (1,325)
Life Insurance Product Line [Member] | Americas [Member] | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs				2,087	1,947
Deferred Policy Acquisition Cost, Capitalization			248	284
Deferred Policy Acquisition Costs, Amortization Expense			(145)	(144)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment			1	0
Life Insurance Product Line [Member] | Americas [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs					1,947
Deferred Policy Acquisition Cost, Capitalization					254
Deferred Policy Acquisition Costs, Amortization Expense					(123)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment					0
Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member] | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs				171	191
Deferred Policy Acquisition Cost, Capitalization			9	10
Deferred Policy Acquisition Costs, Amortization Expense			(12)	(17)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment			5	(13)
Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs					191
Deferred Policy Acquisition Cost, Capitalization					8
Deferred Policy Acquisition Costs, Amortization Expense					(13)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment					1
Life Insurance Product Line [Member] | EMEA [Member] | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs				294	270
Deferred Policy Acquisition Cost, Capitalization			100	83
Deferred Policy Acquisition Costs, Amortization Expense			(50)	(38)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment			3	(21)
Life Insurance Product Line [Member] | EMEA [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs					270
Deferred Policy Acquisition Cost, Capitalization					42
Deferred Policy Acquisition Costs, Amortization Expense					(24)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment					(12)
Life Insurance Product Line [Member] | Asia Pacific [Member] | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs				1,043	1,056
Deferred Policy Acquisition Cost, Capitalization			121	86
Deferred Policy Acquisition Costs, Amortization Expense			(59)	(67)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment			(7)	(32)
Life Insurance Product Line [Member] | Asia Pacific [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs					1,056
Deferred Policy Acquisition Cost, Capitalization					83
Deferred Policy Acquisition Costs, Amortization Expense					(55)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment					(18)
Insurance, Other [Member] | Americas [Member] | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs				341	312
Deferred Policy Acquisition Cost, Capitalization			259	87
Deferred Policy Acquisition Costs, Amortization Expense			(48)	(58)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment			0	0
Insurance, Other [Member] | Americas [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs					312	$ 368
Deferred Policy Acquisition Cost, Capitalization					8
Deferred Policy Acquisition Costs, Amortization Expense					(64)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment					0
Insurance, Other [Member] | Canada Segment Reporting Information [Member] | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs				0	0
Deferred Policy Acquisition Cost, Capitalization			0	0
Deferred Policy Acquisition Costs, Amortization Expense			0	0
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment			0	0
Insurance, Other [Member] | Canada Segment Reporting Information [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs					0	0
Deferred Policy Acquisition Cost, Capitalization					0
Deferred Policy Acquisition Costs, Amortization Expense					0
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment					0
Insurance, Other [Member] | EMEA [Member] | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs				0	0
Deferred Policy Acquisition Cost, Capitalization			0	0
Deferred Policy Acquisition Costs, Amortization Expense			0	0
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment			0	0
Insurance, Other [Member] | EMEA [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs					0	0
Deferred Policy Acquisition Cost, Capitalization					0
Deferred Policy Acquisition Costs, Amortization Expense					0
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment					0
Insurance, Other [Member] | Asia Pacific [Member] | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs				188	81
Deferred Policy Acquisition Cost, Capitalization			99	121
Deferred Policy Acquisition Costs, Amortization Expense			(33)	(13)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment			$ (4)	$ (1)
Insurance, Other [Member] | Asia Pacific [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs					81	$ 41
Deferred Policy Acquisition Cost, Capitalization					49
Deferred Policy Acquisition Costs, Amortization Expense					(8)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment					$ (1)
Cumulative Effect, Period of Adoption, Original Balance | Life Insurance Product Line [Member] | Americas [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							$ 1,816
Cumulative Effect, Period of Adoption, Original Balance | Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							195
Cumulative Effect, Period of Adoption, Original Balance | Life Insurance Product Line [Member] | EMEA [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							264
Cumulative Effect, Period of Adoption, Original Balance | Life Insurance Product Line [Member] | Asia Pacific [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							1,046
Cumulative Effect, Period of Adoption, Original Balance | Insurance, Other [Member] | Americas [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							254
Cumulative Effect, Period of Adoption, Original Balance | Insurance, Other [Member] | Canada Segment Reporting Information [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Original Balance | Insurance, Other [Member] | EMEA [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Original Balance | Insurance, Other [Member] | Asia Pacific [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							41
Cumulative Effect, Period of Adoption, Adjustment | Life Insurance Product Line [Member] | Americas [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Adjustment | Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Adjustment | Life Insurance Product Line [Member] | EMEA [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Adjustment | Life Insurance Product Line [Member] | Asia Pacific [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Adjustment | Insurance, Other [Member] | Americas [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							114
Cumulative Effect, Period of Adoption, Adjustment | Insurance, Other [Member] | Canada Segment Reporting Information [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Adjustment | Insurance, Other [Member] | EMEA [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Adjustment | Insurance, Other [Member] | Asia Pacific [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Adjusted Balance | Life Insurance Product Line [Member] | Americas [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							1,816
Cumulative Effect, Period of Adoption, Adjusted Balance | Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							195
Cumulative Effect, Period of Adoption, Adjusted Balance | Life Insurance Product Line [Member] | EMEA [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							264
Cumulative Effect, Period of Adoption, Adjusted Balance | Life Insurance Product Line [Member] | Asia Pacific [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							1,046
Cumulative Effect, Period of Adoption, Adjusted Balance | Insurance, Other [Member] | Americas [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							368
Cumulative Effect, Period of Adoption, Adjusted Balance | Insurance, Other [Member] | Canada Segment Reporting Information [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Adjusted Balance | Insurance, Other [Member] | EMEA [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							0
Cumulative Effect, Period of Adoption, Adjusted Balance | Insurance, Other [Member] | Asia Pacific [Member] | Accounting Standards Update 2018-12 | Other Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred policy acquisition costs							$ 41