Debt (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2020		Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Debt Disclosure [Abstract]
Loss on early extinguishment of debt	$ 0	[1]	$ 0	$ (168)	$ 0
Long-term Debt, Excluding Current Maturities	1,500			1,500
Debt Instrument [Line Items]
Long-term Debt, Excluding Current Maturities	1,500			1,500
Senior Notes due March 2030 [Member]
Debt Disclosure [Abstract]
Long-term Debt, Excluding Current Maturities	$ 1,000			$ 1,000
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.92%			2.92%
Long-term Debt, Excluding Current Maturities	$ 1,000			$ 1,000
Senior notes due August 2023 [Member]
Debt Disclosure [Abstract]
Long-term Debt, Excluding Current Maturities	$ 500			$ 500
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.50%			3.50%
Long-term Debt, Excluding Current Maturities	$ 500			$ 500
Senior Notes due November 2025 [Member]
Debt Disclosure [Abstract]
Long-term Debt, Excluding Current Maturities	$ 1,000			$ 1,000
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.80%			3.80%
Long-term Debt, Excluding Current Maturities	$ 1,000			$ 1,000

[1] For the six months ended June 30, 2020, amount includes a $168 million loss on extinguishment of debt related to the early repurchase of senior notes. See Note 6 for further discussion on this charge.