Financing arrangements (Principal Amounts and Carrying Value of Long-term Borrowings) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	May 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Commercial paper	$ 960		$ 0
Short-term loan	0		605
Total carrying value of debt	35,062		34,596
Less current portion	(1,459)		(4,403)
Total noncurrent debt	$ 33,603		30,193
2.125% notes due 2017 (2.125% 2017 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent			$ 1,250
Interest rate, stated percentage	2.125%		2.125%
Floating Rate Notes due 2017 [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent			$ 600
1.25% notes due 2017 (1.25% 2017 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent			$ 850
Interest rate, stated percentage	1.25%		1.25%
5.85% notes due 2017 (5.85% 2017 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent			$ 1,100
Interest rate, stated percentage	5.85%		5.85%
6.15% notes due 2018 (6.15% 2018 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 500		$ 500
Interest rate, stated percentage	6.15%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
4.375% €550 million notes due 2018 (4.375% 2018 euro Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 620		577
Interest rate, stated percentage	4.375%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
5.70% notes due 2019 (5.70% 2019 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 1,000		1,000
Interest rate, stated percentage	5.70%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
1.90% notes due 2019 (1.90% 2019 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 700
Interest rate, stated percentage	1.90%	1.90%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
Floating Rate Notes due 2019 [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 550		250
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
2.20% notes due 2019 (2.20% 2019 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 1,400		1,400
Interest rate, stated percentage	2.20%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
2.125% Euro Notes Due 2019 [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 771		710
Interest rate, stated percentage	2.125%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
4.50% notes due 2020 (4.50% 2020 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 300		300
Interest rate, stated percentage	4.50%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
2.125% notes due 2020 (2.125% 2020 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 750		750
Interest rate, stated percentage	2.125%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
Floating Rate Notes Due 2020 [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 300
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
2.20% notes due 2020 (2.20% 2020 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 700
Interest rate, stated percentage	2.20%	2.20%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
3.45% notes due 2020 (3.45% 2020 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 900		900
Interest rate, stated percentage	3.45%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
4.10% notes due 2021 (4.10% 2021 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 1,000		1,000
Interest rate, stated percentage	4.10%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
1.85% notes due 2021 (1.85% 2021 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 750		750
Interest rate, stated percentage	1.85%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
3.875% notes due 2021 (3.875% 2021 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 1,750		1,750
Interest rate, stated percentage	3.875%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
1.25% €1,250 million notes due 2022 (1.25% 2022 euro Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 1,429		1,315
Interest rate, stated percentage	1.25%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
2.70% notes due 2022 (2.70% 2022 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 500		500
Interest rate, stated percentage	2.70%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
2.65% notes due 2022 (2.65% 2022 Notes) {Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 1,500
Interest rate, stated percentage	2.65%	2.65%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
3.625% notes due 2022 (3.625% 2022 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 750		750
Interest rate, stated percentage	3.625%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
0.41% Swiss-franc-denominated bonds due 2023 (0.41% 2023 Swiss franc Bonds) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 731		687
Interest rate, stated percentage	0.41%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
2.25% notes due 2023 (2.25% 2023 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 750		750
Interest rate, stated percentage	2.25%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
3.625% notes due 2024 (3.625% 2024 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 1,400		1,400
Interest rate, stated percentage	3.625%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
3.125% notes due 2025 (3.125% 2025 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 1,000		1,000
Interest rate, stated percentage	3.125%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
2.00% €750 million notes due 2026 (2.00% 2026 euro Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 857		789
Interest rate, stated percentage	2.00%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
2.60% notes due 2026 (2.60% 2026 notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 1,250		1,250
Interest rate, stated percentage	2.60%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
5.50% pound-sterling denominated notes due 2026 (5.50% 2026 pound sterling Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 619		586
Interest rate, stated percentage	5.50%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
4.00% pound-sterling denominated notes due 2029 (4.00% 2029 pound sterling Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 912		864
Interest rate, stated percentage	4.00%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
6.375% notes due 2037 (6.375% 2037 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 552		552
Interest rate, stated percentage	6.375%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
6.90% notes due 2038 (6.90% 2038 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 291		291
Interest rate, stated percentage	6.90%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
6.40% notes due 2039 (6.40% 2039 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 466		466
Interest rate, stated percentage	6.40%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
5.75% notes due 2040 (5.75% 2040 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 412		412
Interest rate, stated percentage	5.75%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
4.95% notes due 2041 (4.95% 2041 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 600		600
Interest rate, stated percentage	4.95%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
5.15% notes due 2041 (5.15% 2041 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 974		974
Interest rate, stated percentage	5.15%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
5.65% notes due 2042 (5.65% 2042 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 487		487
Interest rate, stated percentage	5.65%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
5.375% notes due 2043 (5.375% 2043 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 261		261
Interest rate, stated percentage	5.375%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
4.40% notes due 2045 (4.40% 2045 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 2,250		2,250
Interest rate, stated percentage	4.40%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
4.563% notes due 2048 (4.563% 2048 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 1,415		1,415
Interest rate, stated percentage	4.563%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
4.663% notes due 2051 (4.663% 2051 Notes) [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 3,541		3,541
Interest rate, stated percentage	4.663%
Percentage of principal amount of notes that may be paid upon occurrence of change in control triggering event	101.00%
Other Notes Due 2097 [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent	$ 100		100
Notes [Member]
Debt Instrument [Line Items]
Unamortized bond discounts, premiums and issuance costs, net	$ (936)		$ (936)