Long-Term Debt (Debt Borrowings)(Details) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2015
USD ($)
| |
| Senior 4.60% Notes Due 2045 [Member] | |
| Principal amount | $ 1,700 |
| Interest rate | 4.60% |
| Maturity date | 2045 |
| Senior 3.375% Notes Due 2025 [Member] | |
| Principal amount | $ 1,500 |
| Interest rate | 3.375% |
| Maturity date | 2025 |
| Senior 4.60% Notes Due 2046 [Member] | |
| Principal amount | $ 1,490 |
| Interest rate | 4.60% |
| Maturity date | 2046 |
| Senior 4.40% Notes Due 2035 [Member] | |
| Principal amount | $ 800 |
| Interest rate | 4.40% |
| Maturity date | 2035 |
| Current Year Borrowings [Member] | |
| Principal amount | $ 5,490 |