Fair Value Measurements (Schedule Of Carrying And Fair Values Of Long-Term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Jul. 17, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Value	$ 5,180	$ 3,566
Senior Notes | 3.60% Senior Notes Due 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	3.60%
Carrying Value	$ 250	249
Senior Notes | 0.875% 2024 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	0.875%
Carrying Value	$ 298	0
Senior Notes | 3.60% Senior Notes Due 2026
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	3.60%
Carrying Value	$ 745	744
Senior Notes | Loan related to tax-exempt waste disposal revenue bonds due 2027
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Value	$ 11	11
Senior Notes | 1.625% Senior Notes Due 2029
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	1.625%
Carrying Value	$ 786	849	$ 779
Senior Notes | 3.375 Senior Notes Due 2030
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	3.375%
Carrying Value	$ 296	296
Senior Notes | 3.50% Senior Notes Due 2032
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	3.50%
Carrying Value	$ 249	249
Senior Notes | 2.875% Senior Notes Due 2041
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	2.875%
Carrying Value	$ 339	0
Senior Notes | 5.0% 2046 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	5.00%
Carrying Value	$ 678	677
Senior Notes | 4.375% 2047 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	4.375%
Carrying Value	$ 492	491
Senior Notes | 3.125% 2051 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	3.125%
Carrying Value	$ 577	0
Fair Value		0
Senior Notes | 3.375% 2061 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	3.375%
Carrying Value	$ 431	0
Fair Value		0
Senior Notes | 8.73% 2022 RS Cogen Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	8.73%
Carrying Value	$ 19	0
Senior Notes | 2026 Term Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate (percent)	0.20%
Carrying Value	$ 9	0
Fair Value | Senior Notes | 3.60% Senior Notes Due 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	252	259
Fair Value | Senior Notes | 0.875% 2024 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	287	0
Fair Value | Senior Notes | 3.60% Senior Notes Due 2026
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	805	846
Fair Value | Senior Notes | 1.625% Senior Notes Due 2029
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	824	897
Fair Value | Senior Notes | 3.375 Senior Notes Due 2030
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	319	332
Fair Value | Senior Notes | 3.50% Senior Notes Due 2032
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	271	276
Fair Value | Senior Notes | 2.875% Senior Notes Due 2041
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	339	0
Fair Value | Senior Notes | 5.0% 2046 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	885	905
Fair Value | Senior Notes | 4.375% 2047 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	592	597
Fair Value | Senior Notes | 3.125% 2051 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	582
Fair Value | Senior Notes | 3.375% 2061 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	432
Fair Value | Senior Notes | 8.73% 2022 RS Cogen Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	19	0
Fair Value | Senior Notes | 2026 Term Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	9	0
Fair Value | Loan related to tax-exempt waste disposal revenue bonds due 2027 | Loan related to tax-exempt waste disposal revenue bonds due 2027
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	$ 11	$ 11