Derivative Instruments and Hedging Activities Interest Spread on Interest Rate Swaps and Caps (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	$ 60,549,307,000	$ 58,777,783,000	$ 48,445,497,000	$ 36,528,169,000
Average Notional Amount	51,015,819,000	47,549,415,000
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net interest expense (income) on interest rate swaps and caps	(12,600,000)	23,700,000
Net Long Position [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Average Notional Amount	$ 42,700,000,000	$ 37,600,000,000