Fair Value Measurements (Financial Assets And Liabilities Carried At Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets:
Available-for-sale debt securities	$ 27	$ 34
Investment in equity securities	176	111
Cross-currency swap derivative contracts, assets		26
Liabilities:
Cross-currency swap derivative contracts, liabilities	622	112
Deferred compensation plans	111	70
Quoted Prices in Active Market (Level 1)
Assets:
Available-for-sale debt securities	0	0
Investment in equity securities	6	0
Cross-currency swap derivative contracts, assets		0
Liabilities:
Cross-currency swap derivative contracts, liabilities	0	0
Deferred compensation plans	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Available-for-sale debt securities	27	34
Investment in equity securities	0	0
Cross-currency swap derivative contracts, assets		26
Liabilities:
Cross-currency swap derivative contracts, liabilities	622	112
Deferred compensation plans	111	70
Significant Unobservable Inputs (Level 3)
Assets:
Available-for-sale debt securities	0	0
Investment in equity securities	0	0
Cross-currency swap derivative contracts, assets		0
Liabilities:
Cross-currency swap derivative contracts, liabilities	0	0
Deferred compensation plans	$ 0	$ 0