Fair Value Disclosures - Financial Assets and Liabilities Not Recorded at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Financial assets:
HTM securities		$ 20,047
Loans and leases HFI, net of ALLL	$ 298,293	147,455
Financial liabilities:
Time deposits	35,896	16,577
Long-term debt	41,339	23,709
Carrying Amount
Financial assets:
HTM securities	0	20,552
Loans and leases HFI, net of ALLL	298,293	147,455
Financial liabilities:
Time deposits	35,896	16,577
Long-term debt	41,339	23,709
Fair Value | Level 2
Financial assets:
HTM securities	0	20,047
Financial liabilities:
Time deposits	35,885	16,617
Long-term debt	42,051	23,723
Fair Value | Level 3
Financial assets:
Loans and leases HFI, net of ALLL	$ 298,586	$ 145,591