Statements of Cash Flows - MEC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income attributable to parent	$ 5,790	$ 6,943	$ 2,950
Adjustments to reconcile net income to net cash flows from operating activities:
Allowance for equity funds	(126)	(165)	(173)
Deferred income taxes and investment tax credits, net	646	1,880	290
Other, net	(169)	(77)	23
Changes in other operating assets and liabilities, net of effects from acquisitions:
Trade receivables and other assets	553	(1,318)	(372)
Pension and other postretirement benefit plans	(39)	(65)	(51)
Accrued property, income and other taxes, net	(489)	(134)	(16)
Accounts payable and other liabilities	163	501	(26)
Net cash flows from operating activities	8,692	6,224	6,206
Cash flows from investing activities:
Capital expenditures	(6,611)	(6,765)	(7,364)
Purchases of marketable securities	(297)	(370)	(262)
Proceeds from sales of marketable securities	273	325	238
Other, net	(74)	76	51
Net cash flows from investing activities	(5,763)	(13,165)	(8,963)
Cash flows from financing activities:
Net (repayments of) proceeds from short-term debt	(276)	(939)	684
Other, net	(79)	(134)	(37)
Net cash flows from financing activities	(3,131)	7,103	3,124
Net change in cash and cash equivalents and restricted cash and cash equivalents	(201)	177	385
Cash and cash equivalents and restricted cash and cash equivalents at beginning of period	1,445	1,268	883
Cash and cash equivalents and restricted cash and cash equivalents at end of period	1,244	1,445	1,268
MEC
Cash flows from operating activities:
Net income attributable to parent	894	826	793
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	914	716	639
Amortization of utility plant to other operating expenses	34	34	33
Allowance for equity funds	(39)	(45)	(78)
Deferred income taxes and investment tax credits, net	153	208	154
Settlements of asset retirement obligations	(103)	(124)	(14)
Other, net	21	(18)	4
Changes in other operating assets and liabilities, net of effects from acquisitions:
Trade receivables and other assets	(293)	48	60
Inventories	44	(52)	(22)
Pension and other postretirement benefit plans	(4)	(19)	(10)
Accrued property, income and other taxes, net	(71)	(64)	(76)
Accounts payable and other liabilities	67	33	7
Net cash flows from operating activities	1,617	1,543	1,490
Cash flows from investing activities:
Capital expenditures	(1,912)	(1,836)	(2,810)
Purchases of marketable securities	(213)	(281)	(156)
Proceeds from sales of marketable securities	207	269	138
Proceeds from sales of other investments	0	2	1
Other investment proceeds	1	9	13
Other, net	6	11	13
Net cash flows from investing activities	(1,911)	(1,826)	(2,801)
Cash flows from financing activities:
Proceeds from long-term debt	492	0	2,326
Repayments of long-term debt	(1)	0	(500)
Net (repayments of) proceeds from short-term debt	0	0	(240)
Other, net	(3)	(2)	(1)
Net cash flows from financing activities	488	(2)	1,585
Net change in cash and cash equivalents and restricted cash and cash equivalents	194	(285)	274
Cash and cash equivalents and restricted cash and cash equivalents at beginning of period	45	330	56
Cash and cash equivalents and restricted cash and cash equivalents at end of period	$ 239	$ 45	$ 330