Derivative Instruments Derivative Instruments (Fair Value Hedge Attributable to Foreign Currency) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Foreign Exchange Contract \| Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	$ (4)	$ (7)	$ (7)	$ (8)
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	3	8	5	13
Foreign Exchange Contract \| Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	0	0	0	0
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	0	$ 0	0	$ 0
Interest Rate Contract \| Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	0		0
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	0		0
Interest Rate Contract \| Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	(2)		(2)
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	$ 2		$ 2

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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-Topic 815
-SubTopic 25
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-Publisher FASB
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
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Amount of gain (loss)recognized in the income statement from the hedging ineffectiveness of a fair value hedge.

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