Common Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Common Equity [Line Items]
Shares available for issuance under the 2020 OIP, Shareowner Direct Plan and 401(k) Savings Plan (in shares)	15,000,000
Proceeds from issuance of common stock, net	$ 247	$ 390	$ 197
Equity Forward Agreements [Member]
Schedule of Common Equity [Line Items]
Common stock issued during the period (in shares)	4,275,127	8,358,973	0
Proceeds from issuance of common stock, net	$ 222	$ 366
Initial forward sale price (in dollars per share)	$ 51.98	$ 43.75
At-the-market Offering Program [Member]
Schedule of Common Equity [Line Items]
Common stock issued during the period (in shares)	0	0	4,171,013
Proceeds from issuance of common stock, net			$ 173
Maximum aggregate gross sales price of common stock that can be offered and sold			175
Fees and commissions from issuance of common stock			$ 2