Statements of Changes in Shareholder's Equity - MEC - USD ($) $ in Millions	Total	Additional Paid-in Capital	Retained Earnings	MEC	MEC Common Stock	MEC Additional Paid-in Capital	MEC Retained Earnings
Balance at Dec. 31, 2019				$ 7,240	$ 0	$ 561	$ 6,679
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to parent	$ 6,943			826			826
Other equity transactions	0	$ (1)		(1)			(1)
Balance at Dec. 31, 2020				8,065	0	561	7,504
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to parent	5,790			894			894
Other equity transactions	(1)			1			1
Balance at Dec. 31, 2021	46,694			8,960	0	561	8,399
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to parent	2,721			961			961
Common stock dividends				(275)			(275)
Other equity transactions	(12)	$ 1	$ (12)	(1)			(1)
Balance at Dec. 31, 2022	$ 46,832			$ 9,645	$ 0	$ 561	$ 9,084