Condensed Parent Company Financial Statements (Condensed Statements Of Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating expenses	$ 2,874	$ 2,676	$ 2,870
Operating income (loss)	795	740	778
Other (income) and deductions:
Equity earnings from consolidated subsidiaries	(62)	(61)	(53)
Interest expense	277	275	273
Total other (income) and deductions	195	173	142
Income before income taxes	600	567	636
Income tax benefit	(74)	(57)	69
Net income	674	624	567
Parent Company [Member]
Operating expenses	5	7	2
Operating income (loss)	(5)	(7)	(2)
Other (income) and deductions:
Equity earnings from consolidated subsidiaries	(664)	(625)	(562)
Interest expense	1	2	9
Other	1	4	7
Total other (income) and deductions	(662)	(619)	(546)
Income before income taxes	657	612	544
Income tax benefit	(5)	(4)	(15)
Net income	$ 662	$ 616	$ 559