Fair Value Measurements, Recurring (Details) - Fair Value, Recurring [Member] - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Assets
Investments in AFS debt securities	$ 26	$ 111
Total gross fair value, assets	1,067	994
Effect of counterparty netting	(824)	(642)
Effect of cash collateral netting	(54)	(66)
Net carrying value on balance sheet, assets	189	286
Liabilities
Blending program obligations	30	58
Total gross fair value, liabilities	919	714
Effect of counterparty netting	(824)	(642)
Effect of cash collateral netting	(59)	(1)
Net carrying value on balance sheet, liabilities	36	71
Assets Held in Trust [Member]
Assets
Investments of certain benefit plans	89	80
Commodity Contracts [Member]
Assets
Derivative contracts	951	803
Effect of counterparty netting	(824)	(642)
Effect of cash collateral netting	(54)	(66)
Derivative contracts, net assets	73	95
Cash collateral received not offset	0	0
Liabilities
Derivative contracts	883	643
Effect of counterparty netting	(824)	(642)
Effect of cash collateral netting	(59)	(1)
Derivative contracts, net liabilities	0	0
Cash collateral paid not offset	(55)	(67)
Physical Purchase Contracts [Member]
Assets
Derivative contracts, not subject to netting	1
Liabilities
Derivative contracts, not subject to netting	5	6
Foreign Currency Contracts [Member]
Liabilities
Derivative contracts, not subject to netting	1	7
Level 1 [Member]
Assets
Investments in AFS debt securities	1	36
Total gross fair value, assets	1,037	915
Liabilities
Blending program obligations	0	0
Total gross fair value, liabilities	884	650
Level 1 [Member] | Assets Held in Trust [Member]
Assets
Investments of certain benefit plans	85	76
Level 1 [Member] | Commodity Contracts [Member]
Assets
Derivative contracts	951	803
Liabilities
Derivative contracts	883	643
Level 1 [Member] | Physical Purchase Contracts [Member]
Assets
Derivative contracts, not subject to netting	0
Liabilities
Derivative contracts, not subject to netting	0	0
Level 1 [Member] | Foreign Currency Contracts [Member]
Liabilities
Derivative contracts, not subject to netting	1	7
Level 2 [Member]
Assets
Investments in AFS debt securities	25	75
Total gross fair value, assets	26	75
Liabilities
Blending program obligations	30	58
Total gross fair value, liabilities	35	64
Level 2 [Member] | Assets Held in Trust [Member]
Assets
Investments of certain benefit plans	0	0
Level 2 [Member] | Commodity Contracts [Member]
Assets
Derivative contracts	0	0
Liabilities
Derivative contracts	0	0
Level 2 [Member] | Physical Purchase Contracts [Member]
Assets
Derivative contracts, not subject to netting	1
Liabilities
Derivative contracts, not subject to netting	5	6
Level 2 [Member] | Foreign Currency Contracts [Member]
Liabilities
Derivative contracts, not subject to netting	0	0
Level 3 [Member]
Assets
Investments in AFS debt securities	0	0
Total gross fair value, assets	4	4
Liabilities
Blending program obligations	0	0
Total gross fair value, liabilities	0	0
Level 3 [Member] | Assets Held in Trust [Member]
Assets
Investments of certain benefit plans	4	4
Level 3 [Member] | Commodity Contracts [Member]
Assets
Derivative contracts	0	0
Liabilities
Derivative contracts	0	0
Level 3 [Member] | Physical Purchase Contracts [Member]
Assets
Derivative contracts, not subject to netting	0
Liabilities
Derivative contracts, not subject to netting	0	0
Level 3 [Member] | Foreign Currency Contracts [Member]
Liabilities
Derivative contracts, not subject to netting	$ 0	$ 0