Debt Long-term Debt Footnote A (Details) - USD ($) $ in Millions |
1 Months Ended | |
---|---|---|
Mar. 31, 2001 |
Mar. 31, 2016 |
|
4.5% U.S. Dollar Notes Due 2046 | ||
Debt Instrument [Line Items] | ||
Debt Instrument, Face Amount | $ 650 | |
Debt Instrument, Term | 30 years | |
Debt instrument, stated interest rate | 4.50% | |
Debt Instrument, Interest Rate, Effective Percentage | 4.58% | |
7.45% U.S. Dollar Debentures Due 2031 | ||
Debt Instrument [Line Items] | ||
Debt Instrument, Face Amount | $ 625 | |
Debt Instrument, Term | 30 years | |
Debt instrument, stated interest rate | 7.45% | |
Debt Instrument, Interest Rate, Effective Percentage | 7.54% |