Debt of the Company (Narrative) (Details) - Senior Notes	Mar. 31, 2017
5.875% notes due 2020
Debt Instrument [Line Items]
Stated interest rate	5.875%
3.400% notes due 2020
Debt Instrument [Line Items]
Stated interest rate	3.40%
5.250% notes due 2021
Debt Instrument [Line Items]
Stated interest rate	5.25%
3.950% notes due 2022
Debt Instrument [Line Items]
Stated interest rate	3.95%
3.625% notes due 2022
Debt Instrument [Line Items]
Stated interest rate	3.625%
4.750% notes due 2025
Debt Instrument [Line Items]
Stated interest rate	4.75%
4.750% notes due 2023
Debt Instrument [Line Items]
Stated interest rate	4.75%
4.250% notes due 2025
Debt Instrument [Line Items]
Stated interest rate	4.25%
2.625% notes due 2024
Debt Instrument [Line Items]
Stated interest rate	2.625%