Stockholders' Equity Preferred and Common Stock (Details) - USD ($) shares in Millions, $ in Millions |
3 Months Ended | ||
|---|---|---|---|
Mar. 31, 2016 |
Mar. 31, 2015 |
Dec. 31, 2015 |
|
| Stockholders' Equity Note [Abstract] | |||
| Preferred Stock, Shares Authorized | 2,000 | ||
| Common Stock, Shares Authorized | 5,000 | ||
| Common Stock, Shares Issued | 1,500 | 1,500 | |
| Common Stock, Shares Outstanding | 1,500 | 1,500 | |
| Common Stock, Shares Purchased During Period | 10 | 10 | |
| Common Stock Purchased, Amount | $ 300 | $ 375 | |
| Dividends Declared on Common Stock | $ 587 | $ 485 | |