Business And Significant Accounting Policies (Narrative) (Details)	3 Months Ended
	Mar. 31, 2022 segment entity item
Business And Significant Accounting Polices [Line Items]
Number of reportable business segments | segment	1
Number of board of directors	13
Number of disinterested directors	7
Direct or indirect ownership interest time period	10 years
Number of board positions to be eliminated upon acquisition	2
Number of directors appointed | entity	2
Sempra Energy [Member]
Business And Significant Accounting Polices [Line Items]
Number of disinterested directors	2
Texas Transmission [Member]
Business And Significant Accounting Polices [Line Items]
Percentage of membership interest owned by non-controlling owners	19.75%
Number of disinterested directors	2
Oncor Holdings [Member]
Business And Significant Accounting Polices [Line Items]
Ownership	80.25%
Number of directors appointed	2
Oncor Holdings [Member] | Sempra Energy [Member]
Business And Significant Accounting Polices [Line Items]
Percentage of membership interest owned by non-controlling owners	51.00%
Ownership holding period	5 years
Minimum [Member]
Business And Significant Accounting Polices [Line Items]
Disinterested directors expenditure budget percentage	10.00%