Statements of Cash Flows - MEC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income (loss)	$ 3,020	$ 2,721	$ 5,790
Adjustments to reconcile net income to net cash flows from operating activities:
Allowance for equity funds	(267)	(167)	(126)
Deferred income taxes and investment tax credits, net	(257)	(467)	646
Other, net	(46)	59	(57)
Changes in other operating assets and liabilities, net of effects from acquisitions:
Trade receivables and other assets	(134)	150	553
Pension and other postretirement benefit plans	(10)	(27)	(39)
Accrued property, income and other taxes, net	(58)	397	(489)
Accounts payable and other liabilities	280	579	163
Net cash flows from operating activities	7,132	9,359	8,692
Cash flows from investing activities:
Capital expenditures	(9,148)	(7,505)	(6,611)
Purchases of marketable securities	(314)	(574)	(297)
Proceeds from sales of marketable securities	2,520	2,464	273
Other, net	17	(28)	(94)
Net cash flows from investing activities	(5,899)	(7,750)	(5,763)
Cash flows from financing activities:
Other, net	(54)	(274)	(70)
Net cash flows from financing activities	(1,250)	(1,006)	(3,131)
Net change in cash and cash equivalents and restricted cash and cash equivalents	(6)	573	(201)
Cash and cash equivalents and restricted cash and cash equivalents at beginning of period	1,817	1,244	1,445
Cash and cash equivalents and restricted cash and cash equivalents at end of period	1,811	1,817	1,244
MEC
Cash flows from operating activities:
Net income (loss)	982	961	894
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	908	1,168	914
Amortization of utility plant to other operating expenses	34	35	34
Allowance for equity funds	(59)	(51)	(39)
Deferred income taxes and investment tax credits, net	90	33	153
Settlements of asset retirement obligations	(21)	(85)	(103)
Other, net	46	51	21
Changes in other operating assets and liabilities, net of effects from acquisitions:
Trade receivables and other assets	254	(11)	(293)
Inventories	(87)	(43)	44
Pension and other postretirement benefit plans	3	8	(4)
Accrued property, income and other taxes, net	76	40	(71)
Accounts payable and other liabilities	(9)	68	67
Net cash flows from operating activities	2,217	2,174	1,617
Cash flows from investing activities:
Capital expenditures	(1,833)	(1,869)	(1,912)
Purchases of marketable securities	(243)	(499)	(213)
Proceeds from sales of marketable securities	227	492	207
Other, net	12	9	7
Net cash flows from investing activities	(1,837)	(1,867)	(1,911)
Cash flows from financing activities:
Common stock dividends	(1,025)	(275)	0
Proceeds from long-term debt	1,338	0	492
Repayments of long-term debt	(317)	(2)	(1)
Other, net	(2)	(1)	(3)
Net cash flows from financing activities	(6)	(278)	488
Net change in cash and cash equivalents and restricted cash and cash equivalents	374	29	194
Cash and cash equivalents and restricted cash and cash equivalents at beginning of period	268	239	45
Cash and cash equivalents and restricted cash and cash equivalents at end of period	$ 642	$ 268	$ 239