Supplemental Cash Flow Disclosures - EEGH (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	$ 1,290	$ 1,040
Restricted cash and cash equivalents	140	212
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	1,445	1,268	$ 883	$ 1,283
Interest paid, net of amounts capitalized	1,855	1,723	1,713
Supplemental disclosure of non-cash investing and financing transactions:
Accrued capital expenditures	801	888	823
Eastern Energy Gas Holdings, LLC [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	35	27
Restricted cash and cash equivalents	13	12
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	48	39	198	$ 57
Interest paid, net of amounts capitalized	317	291	162
Income taxes paid	31	65	79
Supplemental disclosure of non-cash investing and financing transactions:
Accrued capital expenditures	30	25	59
Distribution of Questar Pipeline Group	(699)	0	0
Distribution of 50% interest in Cove Point	(2,765)	0	0
Acquisition of Eastern Energy Gas by BHE	343	0	0
Equity contributions	$ 0	$ 0	$ 23