Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies (Details) $ in Millions		3 Months Ended	6 Months Ended
	Mar. 31, 2024 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2024 USD ($) segment	Jan. 01, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of loan portfolio segments | segment			4
Financing receivable, allowance for credit loss, excluding accrued interest, forecast period	12 months	24 months
Financing receivable, allowance for credit loss, excluding accrued interest, reversion period	24 months	12 months
Opening retained earnings	$ 13,657	$ 13,851	$ 13,851		$ 13,766	$ 13,532	$ 13,378	$ 12,859
Retained earnings (accumulated deficit)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Opening retained earnings	$ 188	$ 360	$ 360		$ 154	$ 23	$ (185)	$ (384)
Retained earnings (accumulated deficit) | Accounting Standards Update 2023-02 | Adoption of Accounting Standards Update 2023-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Opening retained earnings				$ (2)