Debt of the Company (Narrative) (Details)	Mar. 31, 2019
3.400% notes due 2020
Debt Instrument [Line Items]
Stated interest rate	3.40%
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%
2.750% notes due 2024
Debt Instrument [Line Items]
Stated interest rate	2.75%
2.625% notes due 2024
Debt Instrument [Line Items]
Stated interest rate	2.625%
Senior Notes | 3.400% notes due 2020
Debt Instrument [Line Items]
Stated interest rate	3.40%
Senior Notes | 5.250% notes due 2021
Debt Instrument [Line Items]
Stated interest rate	5.25%
Senior Notes | 3.950% notes due 2022
Debt Instrument [Line Items]
Stated interest rate	3.95%
Senior Notes | 3.625% notes due 2022
Debt Instrument [Line Items]
Stated interest rate	3.625%
Senior Notes | 2.750% notes due 2023
Debt Instrument [Line Items]
Stated interest rate	2.75%
Senior Notes | 4.750% notes due 2025
Debt Instrument [Line Items]
Stated interest rate	4.75%
Senior Notes | 3.700% notes due 2027
Debt Instrument [Line Items]
Stated interest rate	3.70%
Senior Notes | 4.450% notes due 2028
Debt Instrument [Line Items]
Stated interest rate	4.45%
Senior Notes | 4.750% notes due 2023
Debt Instrument [Line Items]
Stated interest rate	4.75%
Senior Notes | 2.750% notes due 2024
Debt Instrument [Line Items]
Stated interest rate	2.75%
Senior Notes | 4.250% notes due 2025
Debt Instrument [Line Items]
Stated interest rate	4.25%
Senior Notes | 3.300% notes due 2029
Debt Instrument [Line Items]
Stated interest rate	3.30%
Senior Notes | 3.750% notes due 2030
Debt Instrument [Line Items]
Stated interest rate	3.75%
Senior Notes | 2.625% notes due 2024
Debt Instrument [Line Items]
Stated interest rate	2.625%
Senior Notes | 2.500% notes due 2026
Debt Instrument [Line Items]
Stated interest rate	2.50%