Condensed Consolidating Financial Statements - Cash Flows (Detail) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Condensed Cash Flow Statements Captions [Line Items]
Operating activities	$ 2,658	$ 2,388
Investing activities	(1,506)	(1,050)
Financing activities	(1,015)	(1,331)
Effect of exchange rate changes on cash, cash equivalents and restricted cash and cash equivalents		1
Increase in cash, cash equivalents and restricted cash and cash equivalents	137	8
Cash, cash equivalents and restricted cash and cash equivalents at beginning of period	293	94
Cash, cash equivalents and restricted cash and cash equivalents at end of period	430	102
Non-Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Condensed Cash Flow Statements Captions [Line Items]
Operating activities	2,658	2,388
Investing activities	(1,506)	(1,050)
Financing activities	(1,015)	(1,331)
Effect of exchange rate changes on cash, cash equivalents and restricted cash and cash equivalents		1
Increase in cash, cash equivalents and restricted cash and cash equivalents	137	8
Cash, cash equivalents and restricted cash and cash equivalents at beginning of period	293	94
Cash, cash equivalents and restricted cash and cash equivalents at end of period	$ 430	$ 102

Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3521-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=98513485&loc=SL98516268-108586

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
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Amount of increase (decrease) in cash, cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; including effect from exchange rate change. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 230
-Section 45
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-URI http://asc.fasb.org/extlink&oid=98513438&loc=d3e33268-110906

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

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Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3521-108585

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