Statements of Cash Flows (Unaudited) - MEC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net income (loss)	$ (129)	$ 4
Adjustments to reconcile net (loss) income to net cash flows from operating activities:
Allowance for equity funds	(38)	(26)
Deferred income taxes and investment tax credits, net	(203)	(135)
Other, net	6	9
Changes in other operating assets and liabilities, net of effects from acquisitions:
Trade receivables and other assets	333	(249)
Pension and other postretirement benefit plans	(11)	(21)
Accrued property, income and other taxes, net	(347)	(453)
Accounts payable and other liabilities	91	19
Net cash flows from operating activities	2,221	1,525
Cash flows from investing activities:
Capital expenditures	(1,553)	(1,295)
Purchases of marketable securities	(170)	(128)
Proceeds from sales of marketable securities	149	104
Other, net	19	(29)
Net cash flows from investing activities	(1,572)	(1,374)
Cash flows from financing activities:
Net (repayments of) proceeds from short-term debt	(165)	409
Other, net	(240)	(9)
Net cash flows from financing activities	(310)	(191)
Net change in cash and cash equivalents and restricted cash and cash equivalents	338	(39)
Cash and cash equivalents and restricted cash and cash equivalents at beginning of period	1,244	1,445
Cash and cash equivalents and restricted cash and cash equivalents at end of period	1,582	1,406
MEC
Cash flows from operating activities:
Net income (loss)	244	147
Adjustments to reconcile net (loss) income to net cash flows from operating activities:
Depreciation and amortization	250	207
Amortization of utility plant to other operating expenses	9	8
Allowance for equity funds	(15)	(6)
Deferred income taxes and investment tax credits, net	16	154
Settlements of asset retirement obligations	(7)	(4)
Other, net	10	(18)
Changes in other operating assets and liabilities, net of effects from acquisitions:
Trade receivables and other assets	42	(299)
Inventories	49	46
Pension and other postretirement benefit plans	3	1
Accrued property, income and other taxes, net	(244)	(331)
Accounts payable and other liabilities	3	10
Net cash flows from operating activities	360	(85)
Cash flows from investing activities:
Capital expenditures	(459)	(298)
Purchases of marketable securities	(105)	(52)
Proceeds from sales of marketable securities	102	47
Other, net	1	0
Net cash flows from investing activities	(461)	(303)
Cash flows from financing activities:
Repayments of long-term debt	(1)	0
Net (repayments of) proceeds from short-term debt	0	387
Other, net	1	0
Net cash flows from financing activities	0	387
Net change in cash and cash equivalents and restricted cash and cash equivalents	(101)	(1)
Cash and cash equivalents and restricted cash and cash equivalents at beginning of period	239	45
Cash and cash equivalents and restricted cash and cash equivalents at end of period	$ 138	$ 44