Loans - Narrative (Details) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) loan_segment	Jun. 30, 2020 USD ($)	Dec. 31, 2020 loan_segment
Receivables [Abstract]
Number of portfolio segments \| loan_segment			3		3
Net gains (losses) on sales of loans and lending-related commitments	$ 62	$ 725	$ 194	$ (188)
Net gains (losses) on sales of loans	$ 47	$ 42	$ 182	$ (100)

The net gain (loss) resulting from a sale of loans, including adjustments to record loans classified as held-for-sale at the lower-of-cost-or-market and fair value adjustments to loan held for investment purposes.

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