Investment Securities - Net Gains on Non-marketable and Other Equity Securities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Gain (Loss) on Securities [Line Items]
Total net gains on non-marketable and other equity securities	$ 305	$ 35	$ 472	$ 20
Non-marketable securities
Gain (Loss) on Securities [Line Items]
Less: realized net gains on sales of non-marketable and other equity securities	61	0	127	0
Net gains on non-marketable and other equity securities still held	244	35	345	20
Non-marketable securities | Fair value accounting | Consolidated venture capital and private equity fund investments
Gain (Loss) on Securities [Line Items]
Total net gains on non-marketable and other equity securities	19	1	36	4
Non-marketable securities | Fair value accounting | Unconsolidated venture capital and private equity fund investments
Gain (Loss) on Securities [Line Items]
Total net gains on non-marketable and other equity securities	15	(2)	32	(1)
Non-marketable securities | Fair value accounting | Other investments
Gain (Loss) on Securities [Line Items]
Total net gains on non-marketable and other equity securities	(1)	(1)	12	(4)
Non-marketable securities | Equity method accounting | Consolidated venture capital and private equity fund investments
Gain (Loss) on Securities [Line Items]
Total net gains on non-marketable and other equity securities	250	26	295	18
Non-marketable securities | Equity method accounting | Debt funds
Gain (Loss) on Securities [Line Items]
Total net gains on non-marketable and other equity securities	1	0	2	0
Non-marketable securities | Equity method accounting | Other investments
Gain (Loss) on Securities [Line Items]
Total net gains on non-marketable and other equity securities	3	(2)	3	(3)
Other equity securities | Fair value accounting
Gain (Loss) on Securities [Line Items]
Total net gains on non-marketable and other equity securities	$ 18	$ 13	$ 92	$ 6