Parent Company Financial Information - Statements of Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investments in subsidiaries:
Other assets	$ 3,542	$ 4,062
Total assets	89,092	84,209
Liabilities and equity:
Term borrowings	1,590	1,670
Total liabilities	80,598	75,902
Total equity	8,494	8,307	$ 5,076	$ 4,786
Total liabilities and equity	89,092	84,209
Parent Company
Assets:
Cash	724	827
Notes receivable	3	3
Investments in subsidiaries:
Bank	8,381	8,176
Non-bank	65	88
Other assets	291	274
Total assets	9,464	9,368
Liabilities and equity:
Accrued employee benefits and other liabilities	321	322
Term borrowings	944	1,034
Total liabilities	1,265	1,356
Total equity	8,199	8,012
Total liabilities and equity	$ 9,464	$ 9,368