Summary of Reconciliation of Segment Operating Revenues (Detail) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2017 |
Mar. 31, 2016 |
|
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||
| Segment reporting information, revenue | $ 29,814 | $ 32,171 |
| Operating Segments | ||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||
| Segment reporting information, revenue | 28,754 | 29,927 |
| Corporate and Other | ||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||
| Segment reporting information, revenue | 1,460 | 1,309 |
| Eliminations | ||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||
| Segment reporting information, revenue | $ (400) | (345) |
| Impact of Divested Operations | ||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||
| Segment reporting information, revenue | $ 1,280 | |