|
Summary of Reconciliation of Segment Operating Revenues (Detail) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | |
|---|---|---|
|
Mar. 31, 2015
|
Mar. 31, 2014
|
|
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||
| Operating Revenues | $ 31,984 | $ 30,818 |
| Operating Segments | ||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||
| Operating Revenues | 31,797 | 30,541 |
| Revenue Generated By Assets Sold | ||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||
| Operating Revenues | 128 | |
| Corporate, Eliminations and Other | ||
| Segment Reporting, Revenue Reconciling Item [Line Items] | ||
| Operating Revenues | $ 187 | $ 149 |