Investment Securities - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Marketable Securities [Abstract]
Proceeds from sales		$ 192,000,000	$ 0
Available-for-sale, accrued interest, after allowance for credit loss	$ 22,000,000
Carrying amount of equity method investments without readily determinable fair value	57,000,000	26,000,000
Unrealized gain (loss) for equity investments with readily determinable fair value	7,000,000	$ (7,000,000)
Debt Securities, Available-for-sale, Realized Loss	$ 4,000,000