Financial Instruments and Fair Value Measurements, Summary of cash flow hedges (Details) - Cash flow hedge [Member] - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Interest expense [Member]
Derivative [Line Items]
Pre-tax unrealized gain (loss) to be reclassified to earnings over the next twelve months		$ 3
Foreign currency [Member]
Derivative [Line Items]
Notional value		$ 2,300	$ 2,300
Foreign currency [Member] | Minimum [Member]
Derivative [Line Items]
Expiration date		2021
Foreign currency [Member] | Maximum [Member]
Derivative [Line Items]
Expiration date		2027
Interest rates [Member]
Derivative [Line Items]
Notional value	$ 1,000	$ 1,500	$ 1,500
Description of interest rate cash flow hedge activity	In January 2020, we amended previously existing forward-starting interest rate swaps with a total notional amount of $1,000 million (the “Swaps”) to extend their maturities to July 2023 and April 2024.
Interest rates [Member] | Other assets [Member]
Derivative [Line Items]
Derivative collateral related to the liability position held with counterparties		$ 238
Interest rates [Member] | Minimum [Member]
Derivative [Line Items]
Expiration date		2021
Interest rates [Member] | Maximum [Member]
Derivative [Line Items]
Expiration date		2024