Debt (Schedule of Line of Credit Facilities) (Details) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 950
Syndicated Credit Facility $850 Million [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		850	$ 850
Long-term Line of Credit	[1]	$ 0	0
Line of Credit Facility, Interest Rate Description		Credit rating
Credit Facility 100 Million [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 100
Long-term Line of Credit	[1]	$ 99	60
Line of Credit Facility, Interest Rate Description		Fixed
Syndicated Credit Facility $500 Million [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 500
Long-term Line of Credit	[1]	$ 294	99
Line of Credit Facility, Interest Rate Description		Credit rating and utilization %
Credit Facility 150 Million
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 150
Long-term Line of Credit	[1]	$ 112	97
Line of Credit Facility, Interest Rate Description		Fixed
Credit Facility 200 Million
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 200
Long-term Line of Credit	[1]	$ 200	$ 29
Line of Credit Facility, Interest Rate Description		Fixed

[1] Represents issued but undrawn letters of credit. There was no cash borrowed for the periods presented.