Derivative Financial Instruments - Notional Values (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Notional values	$ 6,200,000
Interest rate swaps
Derivatives, Fair Value [Line Items]
Notional values	6,243,601	$ 8,557,883
Interest rate swaps | Trading
Derivatives, Fair Value [Line Items]
Notional values	766,726	2,693,364
Interest rate swaps | Cash Flow | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional values	1,469,867	1,018,976
Interest rate swaps | Fair Value | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional values	$ 4,007,008	$ 4,845,543