Debt - Short-Term Borrowings (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Short-term Debt [Line Items]
Annualized interest rate	5.63%	5.28%	5.71%
Letters of credit outstanding	$ 115,000	$ 115,000	$ 115,000
Remaining amount available under credit line	$ 561,000	$ 330,000	316,000
Daily-weighted average interest rate (annualized)	5.68%	4.95%
Maximum daily amount outstanding during period (par value)	$ 384,000	$ 477,700
Short-term Debt
Short-term Debt [Line Items]
Balance commercial paper at end of period (at par value)	324,000	305,000	$ 319,000
Commercial paper
Short-term Debt [Line Items]
Average balance of commercial paper outstanding during period (par value)	346,088	293,892
Commercial paper issued during period (par value)	404,000	545,000
Commercial paper matured during period (par value)	(399,000)	(525,000)
Net commercial paper issued (matured) during period (par value)	$ 5,000	$ 20,000