Financial Instruments (Fair Values Of Derivatives Instruments) (Detail) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair Value, Derivative Assets	$ 23	$ 3
Fair Value, Derivative Liabilities	55	80
Derivatives designated as hedging instruments | Interest rate swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair Value, Derivative Assets	6	0
Fair Value, Derivative Liabilities	43	69
Derivatives not designated as hedging instruments | Foreign exchange contract
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair Value, Derivative Assets	16	3
Fair Value, Derivative Liabilities	11	11
Derivatives not designated as hedging instruments | Interest rate contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair Value, Derivative Assets	1	0
Fair Value, Derivative Liabilities	$ 1	$ 0