Quarterly Financial Data (Unaudited) - Summarized Results of Operations (Details) - USD ($) $ / shares in Units, $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 |
Sep. 30, 2019 |
Jun. 30, 2019 |
Mar. 31, 2019 |
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Quarterly Financial Data | |||||||||||
| Operating revenue | $ 11,439 | $ 12,560 | $ 12,536 | $ 10,472 | $ 10,742 | $ 11,953 | $ 11,775 | $ 9,968 | $ 47,007 | $ 44,438 | $ 41,138 |
| Operating Income (Loss) | 1,399 | 2,071 | 2,128 | 1,020 | 1,090 | 1,645 | 1,684 | 844 | 6,618 | 5,264 | 5,966 |
| Net Income | $ 1,099 | $ 1,495 | $ 1,443 | $ 730 | $ 1,019 | $ 1,322 | $ 1,036 | $ 557 | $ 4,767 | $ 3,935 | $ 3,205 |
| Basic earnings per share (usd per share) | $ 1.71 | $ 2.32 | $ 2.22 | $ 1.10 | $ 1.50 | $ 1.93 | $ 1.49 | $ 0.79 | $ 7.32 | $ 5.69 | $ 4.45 |
| Diluted earnings per share (usd per share) | $ 1.71 | $ 2.31 | $ 2.21 | $ 1.09 | $ 1.49 | $ 1.92 | $ 1.49 | $ 0.79 | $ 7.30 | $ 5.67 | $ 4.43 |