Segment Information - Total Revenue by Geographic Region (Detail) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
|
| Segment Reporting Information [Line Items] | ||||
| Revenue | $ 2,965 | $ 2,804 | $ 5,789 | $ 5,428 |
| Americas [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Revenue | 2,012 | 1,876 | 3,951 | 3,646 |
| Europe [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Revenue | 803 | 792 | 1,550 | 1,514 |
| Asia-Pacific [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Revenue | $ 150 | $ 136 | $ 288 | $ 268 |