Acquisition and Divestiture Activity (Acquisition Consideration) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 01, 2021	Dec. 31, 2020
Liabilities
Goodwill	$ 10,958,000		$ 9,233,000
BBVA USA Bancshares, Inc.
Business Acquisition [Line Items]
Fair value of acquisition consideration		$ 11,480,000
Assets
Cash and due from banks		969,000
Interest-earning deposits with banks		13,313,000
Loans held for sale		446,000
Investment securities – available for sale		18,358,000
Net loans		61,370,000
Equity investments		723,000
Mortgage servicing rights		35,000
Core deposit intangibles and other intangible assets		399,000
Other		3,531,000
Total assets		99,144,000
Liabilities
Deposits		85,562,000
Borrowed funds		2,449,000
Accrued expenses and other liabilities		1,271,000
Total liabilities		89,282,000
Noncontrolling interests		22,000
Less: Net assets		9,840,000
Goodwill		$ 1,640,000