Long-Term Debt (Schedule Of Long-Term Debt) (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Total long-term debt	$ 10,912,000,000	$ 10,127,000,000
Unamortized discount and debt issuance costs	(93,000,000)	(95,000,000)
Less amount due currently	(482,000,000)	(882,000,000)
Long-term debt, less amounts due currently	10,337,000,000	9,150,000,000
Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	9,727,000,000	10,127,000,000
Unsecured Debt [Member]
Debt Instrument [Line Items]
Variable rate unsecured long-term debt	$ 1,185,000,000
4.10% Senior Notes Due June 1, 2022 [Member]
Debt Instrument [Line Items]
Interest rate	4.10%
Debt Instrument, Face Amount	$ 400,000,000
4.10% Senior Notes Due June 1, 2022 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt		$ 400,000,000
Interest rate	4.10%	4.10%
7.00% Debentures Due September 1, 2022 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 482,000,000	$ 482,000,000
Interest rate	7.00%	7.00%
2.75% Senior Notes due June 1, 2024 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 500,000,000	$ 500,000,000
Interest rate	2.75%	2.75%
2.95% Senior Notes Due April 1, 2025 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 350,000,000	$ 350,000,000
Interest rate	2.95%	2.95%
0.55% Senior Notes Due October 1, 2025 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 450,000,000	$ 450,000,000
Interest rate	0.55%	0.55%
3.86% Senior Notes, Series A, due December 3, 2025 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 174,000,000	$ 174,000,000
Interest rate	3.86%	3.86%
3.86% Senior Notes, Series B, due January 14, 2026 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 38,000,000	$ 38,000,000
Interest rate	3.86%	3.86%
3.70% Senior Notes Due November 15, 2028 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 650,000,000	$ 650,000,000
Interest rate	3.70%	3.70%
5.75% Senior Notes Due March 15, 2029 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 318,000,000	$ 318,000,000
Interest rate	5.75%	5.75%
2.75% Senior Notes Due May 15, 2030 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 700,000,000	$ 700,000,000
Interest rate	2.75%	2.75%
7.00% Senior Notes Due May 1, 2032 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 494,000,000	$ 494,000,000
Interest rate	7.00%	7.00%
7.25% Senior Notes Due January 15, 2033 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 323,000,000	$ 323,000,000
Interest rate	7.25%	7.25%
7.50% Senior Notes Due September 1, 2038 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 300,000,000	$ 300,000,000
Interest rate	7.50%	7.50%
5.25% Senior Notes Due September 30, 2040 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 475,000,000	$ 475,000,000
Interest rate	5.25%	5.25%
4.55% Senior Notes Due December 1, 2041 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 400,000,000	$ 400,000,000
Interest rate	4.55%	4.55%
5.30% Senior Notes Due June 1, 2042 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 348,000,000	$ 348,000,000
Interest rate	5.30%	5.30%
3.75% Senior Notes Due April 1, 2045 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 550,000,000	$ 550,000,000
Interest rate	3.75%	3.75%
3.80% Senior Notes Due September 30, 2047 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 325,000,000	$ 325,000,000
Interest rate	3.80%	3.80%
4.10% Senior Notes Due November 15, 2048 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 450,000,000	$ 450,000,000
Interest rate	4.10%	4.10%
3.80% Senior Notes, Due June 1, 2049 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 500,000,000	$ 500,000,000
Interest rate	3.80%	3.80%
3.10% Senior Notes, Due September 15, 2049 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 700,000,000	$ 700,000,000
Interest rate	3.10%	3.10%
3.70% Senior Notes Due May 15, 2050 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 400,000,000	$ 400,000,000
Interest rate	3.70%	3.70%
2.70% Senior Notes Due November 15, 2051 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 500,000,000	$ 500,000,000
Interest rate	2.70%
5.35% Senior Notes Due October 1, 2052 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Fixed rate secured long-term debt	$ 300,000,000	$ 300,000,000
Interest rate	5.35%	5.35%
June 2021 Term Loan Credit Agreement Maturing August 15, 2022 [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Variable rate unsecured long-term debt	$ 1,185,000,000

Face (par) amount of debt instrument at time of issuance.

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