Consolidated Statements of Changes in Equity (Unaudited) - EEGH - USD ($) $ in Millions	Total	Eastern Energy Gas Holdings, LLC [Member]	Member Interests[Member] Eastern Energy Gas Holdings, LLC [Member]	Accumulated Other Comprehensive (Loss) Income, Net [Member]	Accumulated Other Comprehensive (Loss) Income, Net [Member] Eastern Energy Gas Holdings, LLC [Member]	Noncontrolling Interest [Member]	Noncontrolling Interest [Member] Eastern Energy Gas Holdings, LLC [Member]
Balance at Dec. 31, 2019	$ 32,578	$ 10,229	$ 9,031	$ (1,706)	$ (187)	$ 129	$ 1,385
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	673	202	169				33
Other comprehensive income (loss)	(547)	(84)		(547)	(84)	0
Distributions		(269)	(232)				(37)
Balance at Mar. 31, 2020	32,572	10,078	8,968	(2,253)	(271)	127	1,381
Balance at Dec. 31, 2020	46,977	6,995	2,957	(1,552)	(53)	3,967	4,091
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	110	191	89				102
Other comprehensive income (loss)	112	12		112	8	0	4
Contributions		11	11
Distributions		(131)	(22)				(109)
Balance at Mar. 31, 2021	$ 47,051	$ 7,078	$ 3,035	$ (1,440)	$ (45)	$ 3,962	$ 4,088