Short-Term and Long-Term Debt - Credit Facilities and Letters of Credit (Details) $ in Millions	Dec. 31, 2024 USD ($)
Line of Credit Facility [Line Items]
Maximum Available	$ 3,792
LOCs Issued	1,972
Line of credit beneficiary amount	236
Five-year revolving credit facility
Line of Credit Facility [Line Items]
Maximum Available	2,000
LOCs Issued	250
Five-year revolving credit facility | Letter of Credit
Line of Credit Facility [Line Items]
LOCs Issued	3
LOC facility due August 2031
Line of Credit Facility [Line Items]
Maximum Available	965
LOCs Issued	895
LOC facility due October 2031
Line of Credit Facility [Line Items]
Maximum Available	827
LOCs Issued	$ 827