Debt and lines of credit - Schedule of Long-term Debt Outstanding (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total debt	$ 5,850	$ 5,100
Net unamortized discounts, premiums and issuance costs	(49)	(32)
Total debt, including net unamortized discounts, premiums and issuance costs	5,801	5,068
Current portion of long-term debt	(499)	(749)
Long-term debt	$ 5,302	4,319
Notes due 2019 at 1.65%
Debt Instrument [Line Items]
Long-term debt stated interest rate (in percentage)	1.65%
Total debt	$ 0	750
Notes due 2020 at 1.75%
Debt Instrument [Line Items]
Long-term debt stated interest rate (in percentage)	1.75%
Total debt	$ 500	500
Notes due 2021 at 2.75%
Debt Instrument [Line Items]
Long-term debt stated interest rate (in percentage)	2.75%
Total debt	$ 550	550
Notes due 2022 at 1.85%
Debt Instrument [Line Items]
Long-term debt stated interest rate (in percentage)	1.85%
Total debt	$ 500	500
Notes due 2023 at 2.25%
Debt Instrument [Line Items]
Long-term debt stated interest rate (in percentage)	2.25%
Total debt	$ 500	500
Notes due 2024 at 2.625%
Debt Instrument [Line Items]
Long-term debt stated interest rate (in percentage)	2.625%
Total debt	$ 300	300
Notes due 2027 at 2.90%
Debt Instrument [Line Items]
Long-term debt stated interest rate (in percentage)	2.90%
Total debt	$ 500	500
Notes due 2029 at 2.25%
Debt Instrument [Line Items]
Long-term debt stated interest rate (in percentage)	2.25%
Total debt	$ 750	0
Notes due 2039 at 3.875%
Debt Instrument [Line Items]
Long-term debt stated interest rate (in percentage)	3.875%
Total debt	$ 750	0
Notes due 2048 at 4.15%
Debt Instrument [Line Items]
Long-term debt stated interest rate (in percentage)	4.15%
Total debt	$ 1,500	$ 1,500

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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