Fair Value Measurements - PAC (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, offset	$ (194)	$ (47)
Assets, fair value	8,824	10,843
Derivative liability, offset	107	73
Cash collateral receivable (payable), offset against derivative positions	(87)	26
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	7,742	9,160
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	1,217	1,637
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	59	93
Commodity derivatives | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, offset	(194)	(47)
Derivative assets	477	302
Derivative liability, offset	106	73
Derivative liability	(218)	(266)
Commodity derivatives | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, not subject to master netting arrangement	6	5
Derivative liability, not subject to master netting arrangement	8	2
Commodity derivatives | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, not subject to master netting arrangement	614	271
Derivative liability, not subject to master netting arrangement	206	113
Commodity derivatives | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, not subject to master netting arrangement	51	73
Derivative liability, not subject to master netting arrangement	110	224
PAC | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	871	304
PAC | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	672	208
PAC | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	318	104
PAC | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value	0	0
PAC | Commodity derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash collateral receivable (payable), offset against derivative positions	(78)	5
Cash collateral payable, not offset	12
PAC | Commodity derivatives | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, offset	(119)	(8)
Derivative assets	199	96
Derivative liability, offset	41	13
Derivative liability	(7)	(38)
Cash collateral receivable (payable), offset against derivative positions	(78)	5
Cash collateral payable, not offset	12
PAC | Commodity derivatives | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, not subject to master netting arrangement	0	0
Derivative liability, not subject to master netting arrangement	0	0
PAC | Commodity derivatives | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, not subject to master netting arrangement	318	104
Derivative liability, not subject to master netting arrangement	48	51
PAC | Commodity derivatives | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, not subject to master netting arrangement	0	0
Derivative liability, not subject to master netting arrangement	0	0
PAC | Money market mutual funds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment funds	649	181
PAC | Money market mutual funds | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment funds	649	181
PAC | Money market mutual funds | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment funds	0	0
PAC | Money market mutual funds | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment funds	0	0
PAC | Investment funds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment funds	23	27
PAC | Investment funds | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment funds	23	27
PAC | Investment funds | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment funds	0	0
PAC | Investment funds | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment funds	$ 0	$ 0