Derivative Financial Instruments (Fair Value of Derivatives) (Detail) - USD ($) $ in Millions		Sep. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Derivative Liability		$ 30	$ 19
Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability	[1]	2	2
Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative Liability	[2]	28	17
Interest Rate Contract [Member] | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability		2	2
Interest Rate Contract [Member] | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative Liability		28	17
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Liability		18	12
Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability	[1]	1	1
Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative Liability	[2]	17	11
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability		1	1
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative Liability		17	11
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Liability		12	7
Not Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability	[1]	1	1
Not Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative Liability	[2]	11	6
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability		1	1
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative Liability		$ 11	$ 6

[1] Current derivative liabilities are presented in other current liabilities in the Consolidated Balance Sheets.

[2] Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in the Consolidated Balance Sheets.