Retirement Benefits Plans - Components of Pension Plans with Accumulated Benefit Obligation in Excess of Plan Assets (Details 3) - USD ($) $ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| United States pension liabilities [Member] | ||
| Components of pension plans with an accumulated benefit obligation in excess of plan assets | ||
| Projected benefit obligation | $ 3,376 | $ 3,557 |
| Accumulated benefit obligation | 3,219 | 3,403 |
| Fair value of plan assets | 2,470 | 2,581 |
| Non-United States pension liabilities [Member] | ||
| Components of pension plans with an accumulated benefit obligation in excess of plan assets | ||
| Projected benefit obligation | 1,387 | 1,524 |
| Accumulated benefit obligation | 1,328 | 1,446 |
| Fair value of plan assets | $ 650 | $ 673 |