Summary of Reconciliation of Segment Operating Revenues (Detail) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
|
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||||
| Segment reporting information, revenue | $ 30,548 | $ 30,532 | $ 60,362 | $ 62,703 |
| Operating Segments | ||||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||||
| Segment reporting information, revenue | 29,084 | 29,417 | 57,730 | 59,235 |
| Corporate and Other | ||||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||||
| Segment reporting information, revenue | 1,778 | 1,366 | 3,238 | 2,675 |
| Eliminations | ||||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||||
| Segment reporting information, revenue | (351) | (361) | (751) | (706) |
| Operating Results from Divested Businesses | ||||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||||
| Segment reporting information, revenue | $ 37 | $ 110 | $ 145 | $ 1,499 |