Schedule I - Condensed Financial Information - Income and Comprehensive Income (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Income Statements,Captions [Line Items]
Interest expense	$ (905)	$ (1,019)	$ (991)
NET INCOME FOR COMMON STOCK	1,346	1,101	1,343
Comprehensive Income	$ 1,376	$ 1,095	$ 1,340
Net Income Per Share – Basic (in dollars per share)	$ 3.86	$ 3.29	$ 4.09
Net Income Per Share – Diluted (in dollars per share)	$ 3.85	$ 3.28	$ 4.08
Average Number Of Shares Outstanding—Basic (in shares)	348.4	334.8	328.5
Average Number Of Shares Outstanding—Diluted (in shares)	349.4	335.7	329.5
Parent Company
Condensed Income Statements,Captions [Line Items]
Equity in earnings of subsidiaries	$ 1,369	$ 1,105	$ 1,354
Other income (deductions), net of taxes	14	56	76
Interest expense	(37)	(60)	(87)
NET INCOME FOR COMMON STOCK	1,346	1,101	1,343
Comprehensive Income	$ 1,376	$ 1,095	$ 1,340
Net Income Per Share – Basic (in dollars per share)	$ 3.86	$ 3.29	$ 4.09
Net Income Per Share – Diluted (in dollars per share)	3.85	3.28	4.08
Dividends Declared Per Share (in dollars per share)	$ 3.10	$ 3.06	$ 2.96
Average Number Of Shares Outstanding—Basic (in shares)	348.4	334.8	328.5
Average Number Of Shares Outstanding—Diluted (in shares)	349.4	335.7	329.5