Accounting for Derivative Instruments and Hedging Activities - Pre-tax Effects of Economic Hedges not Designated as Cash Flow Hedges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrealized Mark To Market Results [Abstract]
Reversal of previously recognized unrealized (gains) on settled positions related to economic hedges	$ (41)	$ (55)	$ (68)
Reversal of acquired loss positions related to economic hedges	256	4	6
Net unrealized gains/(losses) on open positions related to economic hedges	2,501	(68)	42
Total unrealized mark-to-market gains/(losses) for economic hedging activities	2,716	(119)	(20)
Reversal of previously recognized unrealized (gains) on settled positions related to trading activity	(18)	(20)	(11)
Reversal of Acquired (gain) Positions Related to Trading Activity	(1)	0	0
Net unrealized (losses)/gains on open positions related to trading activity	(13)	15	31
Total unrealized mark-to-market (losses)/gains for trading activity	(32)	(5)	20
Total unrealized gains/(losses)	2,684	(124)	0
Credit Risk Related Contingent Features [Abstract]
Collateral required contracts with credit rating contingent features in a net liability position	70
Additional collateral required	1
Adequate Assurance Clauses
Credit Risk Related Contingent Features [Abstract]
Collateral required for contracts in net liability positions that have adequate assurance clauses	1,000
Commodity contracts
Unrealized Mark To Market Results [Abstract]
Total unrealized gains/(losses)	2,684	(124)	0
Commodity contracts | Operating revenue
Unrealized Mark To Market Results [Abstract]
Total unrealized gains/(losses)	(196)	90	53
Commodity contracts | Cost of operations
Unrealized Mark To Market Results [Abstract]
Total unrealized gains/(losses)	2,880	(214)	(53)
Interest rate contracts
Unrealized Mark To Market Results [Abstract]
Total unrealized gains/(losses)	$ 0	$ 0	$ (38)