Deposits and Borrowings - Long-Term Debt (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total long-term debt	$ 42,093	$ 48,383
Total short-term borrowings and long-term debt	42,795	55,697
EUR denominated unsecured notes	28,448	30,472
Euro
Debt Instrument [Line Items]
EUR denominated unsecured notes	$ 1,500	1,400
Securitized debt obligations
Debt Instrument [Line Items]
Weighted average interest rate	1.90%
Carrying value	$ 13,566	17,808
Total senior and subordinated notes
Debt Instrument [Line Items]
Carrying value	$ 28,448	30,472
Senior notes \| Total unsecured senior debt
Debt Instrument [Line Items]
Weighted average interest rate	3.01%
Carrying value	$ 23,693	25,997
Senior notes \| Fixed unsecured senior debt
Debt Instrument [Line Items]
Weighted average interest rate	3.19%
Carrying value	$ 21,685	23,302
Senior notes \| Floating unsecured senior debt
Debt Instrument [Line Items]
Weighted average interest rate	1.03%
Carrying value	$ 2,008	2,695
Subordinated notes \| Fixed unsecured subordinated debt
Debt Instrument [Line Items]
Weighted average interest rate	3.78%
Carrying value	$ 4,755	4,475
Finance lease liabilities
Debt Instrument [Line Items]
Weighted average interest rate	3.77%
Carrying value	$ 79	103
Total other long-term borrowings
Debt Instrument [Line Items]
Carrying value	$ 79	$ 103
Minimum \| Securitized debt obligations
Debt Instrument [Line Items]
Stated interest rates	0.50%
Minimum \| Senior notes \| Fixed unsecured senior debt
Debt Instrument [Line Items]
Stated interest rates	0.80%
Minimum \| Senior notes \| Floating unsecured senior debt
Debt Instrument [Line Items]
Stated interest rates	0.70%
Minimum \| Subordinated notes \| Fixed unsecured subordinated debt
Debt Instrument [Line Items]
Stated interest rates	3.38%
Minimum \| Finance lease liabilities
Debt Instrument [Line Items]
Stated interest rates	1.63%
Maximum \| Securitized debt obligations
Debt Instrument [Line Items]
Stated interest rates	3.01%
Maximum \| Senior notes \| Fixed unsecured senior debt
Debt Instrument [Line Items]
Stated interest rates	4.75%
Maximum \| Senior notes \| Floating unsecured senior debt
Debt Instrument [Line Items]
Stated interest rates	1.42%
Maximum \| Subordinated notes \| Fixed unsecured subordinated debt
Debt Instrument [Line Items]
Stated interest rates	4.20%
Maximum \| Finance lease liabilities
Debt Instrument [Line Items]
Stated interest rates	9.91%

Amount of short-term and long-term debt and lease obligation.

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