Fair Value Measurements, Recurring (Details) - Fair Value, Recurring [Member] - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Assets
Investments in AFS debt securities	$ 26	$ 111
Total gross fair value, assets	809	994
Effect of counterparty netting	(664)	(642)
Effect of cash collateral netting	(1)	(66)
Net carrying value on balance sheet, assets	144	286
Liabilities
Blending program obligations	22	58
Total gross fair value, liabilities	739	714
Effect of counterparty netting	(664)	(642)
Effect of cash collateral netting	(41)	(1)
Net carrying value on balance sheet, liabilities	34	71
Assets Held in Trust [Member]
Assets
Investments of certain benefit plans	87	80
Commodity Contracts [Member]
Assets
Derivative contracts	695	803
Effect of counterparty netting	(664)	(642)
Effect of cash collateral netting	(1)	(66)
Derivative contracts, net assets	30	95
Cash collateral received not offset	0	0
Liabilities
Derivative contracts	705	643
Effect of counterparty netting	(664)	(642)
Effect of cash collateral netting	(41)	(1)
Derivative contracts, net liabilities	0	0
Cash collateral paid not offset	(109)	(67)
Physical Purchase Contracts [Member]
Liabilities
Derivative contracts, not subject to netting	11	6
Foreign Currency Contracts [Member]
Assets
Derivative contracts, not subject to netting	1
Liabilities
Derivative contracts, not subject to netting	1	7
Level 1 [Member]
Assets
Investments in AFS debt securities	8	36
Total gross fair value, assets	787	915
Liabilities
Blending program obligations	0	0
Total gross fair value, liabilities	706	650
Level 1 [Member] | Assets Held in Trust [Member]
Assets
Investments of certain benefit plans	83	76
Level 1 [Member] | Commodity Contracts [Member]
Assets
Derivative contracts	695	803
Liabilities
Derivative contracts	705	643
Level 1 [Member] | Physical Purchase Contracts [Member]
Liabilities
Derivative contracts, not subject to netting	0	0
Level 1 [Member] | Foreign Currency Contracts [Member]
Assets
Derivative contracts, not subject to netting	1
Liabilities
Derivative contracts, not subject to netting	1	7
Level 2 [Member]
Assets
Investments in AFS debt securities	18	75
Total gross fair value, assets	18	75
Liabilities
Blending program obligations	22	58
Total gross fair value, liabilities	33	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]
Liabilities
Derivative contracts, not subject to netting	11	6
Level 2 [Member] | Foreign Currency Contracts [Member]
Assets
Derivative contracts, not subject to netting	0
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]
Liabilities
Derivative contracts, not subject to netting	0	0
Level 3 [Member] | Foreign Currency Contracts [Member]
Assets
Derivative contracts, not subject to netting	0
Liabilities
Derivative contracts, not subject to netting	$ 0	$ 0