Derivative Instruments and Hedging Activities (Notional and Recorded Fair Values) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Derivative [Line Items]
Notional amount	$ 22,148,000	$ 24,498,000
Derivative asset, fair value	420,000	386,000
Derivative liability, fair value	333,000	451,000
Net credit valuation adjustment reducing fair value	9,000	13,000
Other assets
Derivative [Line Items]
Derivative asset, fair value	420,000	386,000
Other liabilities
Derivative [Line Items]
Derivative liability, fair value	333,000	451,000
Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount	6,521,000	9,361,000
Derivatives designated as hedging instruments | Other assets
Derivative [Line Items]
Derivative asset, fair value	78,000	84,000
Derivatives designated as hedging instruments | Other liabilities
Derivative [Line Items]
Derivative liability, fair value	0	1,000
Derivatives designated as hedging instruments | Interest rate swaps | Cash Flow Hedging
Derivative [Line Items]
Notional amount	1,450,000	7,633,000
Derivatives designated as hedging instruments | Interest rate swaps | Fair Value Hedging
Derivative [Line Items]
Notional amount	0	500,000
Derivatives designated as hedging instruments | Interest rate swaps | Other assets | Cash Flow Hedging
Derivative [Line Items]
Derivative asset, fair value	0	0
Derivatives designated as hedging instruments | Interest rate swaps | Other assets | Fair Value Hedging
Derivative [Line Items]
Derivative asset, fair value	0	0
Derivatives designated as hedging instruments | Interest rate swaps | Other liabilities | Cash Flow Hedging
Derivative [Line Items]
Derivative liability, fair value	0	1,000
Derivatives designated as hedging instruments | Interest rate swaps | Other liabilities | Fair Value Hedging
Derivative [Line Items]
Derivative liability, fair value	0	0
Derivatives designated as hedging instruments | Receive-fixed interest rate swaps | Cash Flow Hedging
Derivative [Line Items]
Notional amount	500,000	0
Derivatives designated as hedging instruments | Receive-fixed interest rate swaps | Other assets | Cash Flow Hedging
Derivative [Line Items]
Derivative asset, fair value	0	0
Derivatives designated as hedging instruments | Receive-fixed interest rate swaps | Other liabilities | Cash Flow Hedging
Derivative [Line Items]
Derivative liability, fair value	0	0
Derivatives designated as hedging instruments | Asset hedges: Pay-fixed interest rate swaps 1 | Fair Value Hedging
Derivative [Line Items]
Notional amount	4,571,000	1,228,000
Derivatives designated as hedging instruments | Asset hedges: Pay-fixed interest rate swaps 1 | Other assets | Fair Value Hedging
Derivative [Line Items]
Derivative asset, fair value	78,000	84,000
Derivatives designated as hedging instruments | Asset hedges: Pay-fixed interest rate swaps 1 | Other liabilities | Fair Value Hedging
Derivative [Line Items]
Derivative liability, fair value	0	0
Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional amount	15,627,000	15,137,000
Derivatives not designated as hedging instruments | Other assets
Derivative [Line Items]
Derivative asset, fair value	342,000	302,000
Derivatives not designated as hedging instruments | Other liabilities
Derivative [Line Items]
Derivative liability, fair value	333,000	450,000
Derivatives not designated as hedging instruments | Customer interest rate derivatives
Derivative [Line Items]
Notional amount	14,375,000	13,670,000
Derivatives not designated as hedging instruments | Customer interest rate derivatives | Other assets
Derivative [Line Items]
Derivative asset, fair value	337,000	296,000
Derivatives not designated as hedging instruments | Customer interest rate derivatives | Other liabilities
Derivative [Line Items]
Derivative liability, fair value	330,000	443,000
Derivatives not designated as hedging instruments | Other interest rate derivatives
Derivative [Line Items]
Notional amount	1,001,000	862,000
Derivatives not designated as hedging instruments | Other interest rate derivatives | Other assets
Derivative [Line Items]
Derivative asset, fair value	1,000	0
Derivatives not designated as hedging instruments | Other interest rate derivatives | Other liabilities
Derivative [Line Items]
Derivative liability, fair value	0	0
Derivatives not designated as hedging instruments | Foreign exchange derivatives
Derivative [Line Items]
Notional amount	216,000	605,000
Derivatives not designated as hedging instruments | Foreign exchange derivatives | Other assets
Derivative [Line Items]
Derivative asset, fair value	3,000	6,000
Derivatives not designated as hedging instruments | Foreign exchange derivatives | Other liabilities
Derivative [Line Items]
Derivative liability, fair value	3,000	7,000
Derivatives not designated as hedging instruments | Purchased credit derivatives
Derivative [Line Items]
Notional amount	35,000	0
Derivatives not designated as hedging instruments | Purchased credit derivatives | Other assets
Derivative [Line Items]
Derivative asset, fair value	1,000	0
Derivatives not designated as hedging instruments | Purchased credit derivatives | Other liabilities
Derivative [Line Items]
Derivative liability, fair value	$ 0	$ 0