Fair Value Measurements, Including Derivatives (Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - Fair value, recurring - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Assets
Total assets	$ 306	$ 401
Liabilities
Total liabilities	8	1
Commodity Contract [Member]
Assets
Derivatives	271	370
Liabilities
Total liabilities	7
Interest Rate Contract [Member]
Assets
Derivatives	2	2
Liabilities
Derivatives	1	1
Cash Equivalents and Other [Member]
Assets
Investments	33	29
Level 1
Assets
Total assets	33	29
Liabilities
Total liabilities	0	0
Level 1 | Commodity Contract [Member]
Assets
Derivatives	0	0
Liabilities
Total liabilities	0
Level 1 | Interest Rate Contract [Member]
Assets
Derivatives	0	0
Liabilities
Derivatives	0	0
Level 1 | Cash Equivalents and Other [Member]
Assets
Investments	33	29
Level 2
Assets
Total assets	3	2
Liabilities
Total liabilities	3	1
Level 2 | Commodity Contract [Member]
Assets
Derivatives	1	0
Liabilities
Total liabilities	2
Level 2 | Interest Rate Contract [Member]
Assets
Derivatives	2	2
Liabilities
Derivatives	1	1
Level 2 | Cash Equivalents and Other [Member]
Assets
Investments	0	0
Level 3
Assets
Total assets	270	370
Liabilities
Total liabilities	5	0
Level 3 | Commodity Contract [Member]
Assets
Derivatives	270	370
Liabilities
Total liabilities	5
Level 3 | Interest Rate Contract [Member]
Assets
Derivatives	0	0
Liabilities
Derivatives	0	0
Level 3 | Cash Equivalents and Other [Member]
Assets
Investments	$ 0	$ 0