Investments - General, Narrative (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Investments [Abstract]
Investment securities in a continuous unrealized loss position for less then 12 months	$ 1,600,000,000		$ 1,600,000,000		$ 2,800,000,000
Investment securities unrealized loss	2,000,000		2,000,000		32,000,000
Estimated fair value for securities in continuous unrealized loss position for greater than 12 months	1,300,000,000		1,300,000,000		952,000,000
Investment securities in a continuous loss position for greater than 12 months, unrealized losses	(77,000,000)		(77,000,000)		$ (66,000,000)
Downward adjustments to the carrying value	0	$ 0	0	$ 7,000,000
Cumulative upward adjustments for observable price changes	41,000,000		41,000,000
Cumulative downward adjustments for price changes and impairment	$ 298,000,000		$ 298,000,000

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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