Segment Information - Total Revenue by Geographic Region (Detail) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Segment Reporting Information [Line Items] | ||
| Revenue | $ 3,583 | $ 3,092 |
| Americas [Member] | ||
| Segment Reporting Information [Line Items] | ||
| Revenue | 2,324 | 2,043 |
| Europe [Member] | ||
| Segment Reporting Information [Line Items] | ||
| Revenue | 1,093 | 906 |
| Asia-Pacific [Member] | ||
| Segment Reporting Information [Line Items] | ||
| Revenue | $ 166 | $ 143 |