Fair Value Measurements, Recurring (Details) - Fair Value, Recurring [Member] - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Assets
Total gross fair value, assets	$ 616	$ 498
Effect of counterparty netting	(444)	(373)
Effect of cash collateral netting	(15)	(18)
Net carrying value on Balance Sheet, assets	157	107
Liabilities
Blending program obligations	57	96
Total gross fair value, liabilities	544	505
Effect of counterparty netting	(444)	(373)
Effect of cash collateral netting	(28)	(32)
Net carrying value on Balance Sheet, liabilities	72	100
Assets Held in Trust [Member]
Assets
Investments of certain benefit plans	89	82
Commodity Contracts [Member]
Assets
Derivative contracts	522	403
Effect of counterparty netting	(444)	(373)
Effect of cash collateral netting	(15)	(18)
Derivative contracts, net assets	63	12
Cash collateral received not offset	0	0
Liabilities
Derivative contracts	472	405
Effect of counterparty netting	(444)	(373)
Effect of cash collateral netting	(28)	(32)
Derivative contracts, net liabilities	0	0
Cash collateral paid not offset	(41)	(44)
Physical Purchase Contracts [Member]
Assets
Derivative contracts	4	13
Derivative contracts, net assets	4	13
Liabilities
Derivative contracts	5
Derivative contracts, net liabilities	5
Foreign Currency Contracts [Member]
Assets
Derivative contracts	1
Derivative contracts, net assets	1
Liabilities
Derivative contracts	10	4
Derivative contracts, net liabilities	10	4
Fair Value, Inputs, Level 1 [Member]
Assets
Total gross fair value, assets	606	477
Liabilities
Blending program obligations	0	0
Total gross fair value, liabilities	482	409
Fair Value, Inputs, Level 1 [Member] | Assets Held in Trust [Member]
Assets
Investments of certain benefit plans	83	74
Fair Value, Inputs, Level 1 [Member] | Commodity Contracts [Member]
Assets
Derivative contracts	522	403
Liabilities
Derivative contracts	472	405
Fair Value, Inputs, Level 1 [Member] | Physical Purchase Contracts [Member]
Assets
Derivative contracts	0	0
Liabilities
Derivative contracts	0
Fair Value, Inputs, Level 1 [Member] | Foreign Currency Contracts [Member]
Assets
Derivative contracts	1
Liabilities
Derivative contracts	10	4
Fair Value, Inputs, Level 2 [Member]
Assets
Total gross fair value, assets	4	13
Liabilities
Blending program obligations	57	96
Total gross fair value, liabilities	62	96
Fair Value, Inputs, Level 2 [Member] | Assets Held in Trust [Member]
Assets
Investments of certain benefit plans	0	0
Fair Value, Inputs, Level 2 [Member] | Commodity Contracts [Member]
Assets
Derivative contracts	0	0
Liabilities
Derivative contracts	0	0
Fair Value, Inputs, Level 2 [Member] | Physical Purchase Contracts [Member]
Assets
Derivative contracts	4	13
Liabilities
Derivative contracts	5
Fair Value, Inputs, Level 2 [Member] | Foreign Currency Contracts [Member]
Assets
Derivative contracts	0
Liabilities
Derivative contracts	0	0
Fair Value, Inputs, Level 3 [Member]
Assets
Total gross fair value, assets	6	8
Liabilities
Blending program obligations	0	0
Total gross fair value, liabilities	0	0
Fair Value, Inputs, Level 3 [Member] | Assets Held in Trust [Member]
Assets
Investments of certain benefit plans	6	8
Fair Value, Inputs, Level 3 [Member] | Commodity Contracts [Member]
Assets
Derivative contracts	0	0
Liabilities
Derivative contracts	0	0
Fair Value, Inputs, Level 3 [Member] | Physical Purchase Contracts [Member]
Assets
Derivative contracts	0	0
Liabilities
Derivative contracts	0
Fair Value, Inputs, Level 3 [Member] | Foreign Currency Contracts [Member]
Assets
Derivative contracts	0
Liabilities
Derivative contracts	$ 0	$ 0