Dispositions and Impairments (Significant Non-cash Items, Capital Expenditures, and Significant Financing Activities of Discontinued Operations) (Details) - DT Midstream - Discontinued operations, spinoff - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities
Depreciation and amortization	$ 82	$ 151	$ 94
Deferred income taxes	53	125	78
Equity earnings of equity method investees	(59)	(106)	(97)
Asset (gains) losses and impairments, net	19	(2)	1
Investing Activities
Plant and equipment expenditures — non-utility	(60)	(517)	(214)
Acquisitions related to business combinations, net of cash acquired	0	0	(2,296)
Financing Activities
Purchase of noncontrolling interest	0	0	(297)
Acquisition related deferred payment, excluding accretion	$ 0	$ (380)	$ 0