Subsequent Events (Details) - High Yield Bonds [Member] $ in Millions	Mar. 31, 2020 USD ($)
April 2020 Senior Unsecured 4.150% Notes [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 500
Debt Instrument, Interest Rate, Stated Percentage	4.15%
April 2020 Senior Unsecured 3.100% Notes [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 750
Debt Instrument, Interest Rate, Stated Percentage	3.30%
April 2020 Senior Notes [Domain] [Domain]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 1,250