Fair value measurement (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Assets:
Interest-bearing securities	$ 5,853	$ 7,304
Equity securities	643	831
Derivatives:
Total assets	6,796	8,400
Derivatives:
Contingent consideration obligations	330	342	$ 39	$ 33
Total liabilities	1,195	876
Foreign currency contracts [Member]
Derivatives:
Foreign currency and cross-currency swap contracts	235	183
Derivatives:
Foreign currency and cross-currency swap contracts	51	39
Cross-currency swap contracts [Member]
Derivatives:
Foreign currency and cross-currency swap contracts	65	66
Derivatives:
Foreign currency and cross-currency swap contracts	358	339
Interest rate swap contracts [Member]
Derivatives:
Interest rate swap contracts	0	16
Derivatives:
Interest rate swap contracts	456	156
Quoted prices in active markets for identical assets (Level 1) [Member]
Assets:
Equity securities	473	611
Derivatives:
Total assets	6,326	7,914
Derivatives:
Contingent consideration obligations	0	0
Total liabilities	0	0
Quoted prices in active markets for identical assets (Level 1) [Member] | Foreign currency contracts [Member]
Derivatives:
Foreign currency and cross-currency swap contracts	0	0
Derivatives:
Foreign currency and cross-currency swap contracts	0	0
Quoted prices in active markets for identical assets (Level 1) [Member] | Cross-currency swap contracts [Member]
Derivatives:
Foreign currency and cross-currency swap contracts	0	0
Derivatives:
Foreign currency and cross-currency swap contracts	0	0
Quoted prices in active markets for identical assets (Level 1) [Member] | Interest rate swap contracts [Member]
Derivatives:
Interest rate swap contracts	0	0
Derivatives:
Interest rate swap contracts	0	0
Significant other observable inputs (Level 2) [Member]
Assets:
Equity securities	0	0
Derivatives:
Total assets	300	266
Derivatives:
Contingent consideration obligations	0	0
Total liabilities	865	534
Significant other observable inputs (Level 2) [Member] | Foreign currency contracts [Member]
Derivatives:
Foreign currency and cross-currency swap contracts	235	183
Derivatives:
Foreign currency and cross-currency swap contracts	51	39
Significant other observable inputs (Level 2) [Member] | Cross-currency swap contracts [Member]
Derivatives:
Foreign currency and cross-currency swap contracts	65	66
Derivatives:
Foreign currency and cross-currency swap contracts	358	339
Significant other observable inputs (Level 2) [Member] | Interest rate swap contracts [Member]
Derivatives:
Interest rate swap contracts	0	16
Derivatives:
Interest rate swap contracts	456	156
Significant unobservable inputs (Level 3) [Member]
Assets:
Equity securities	170	220
Derivatives:
Total assets	170	220
Derivatives:
Contingent consideration obligations	330	342
Total liabilities	330	342
Significant unobservable inputs (Level 3) [Member] | Foreign currency contracts [Member]
Derivatives:
Foreign currency and cross-currency swap contracts	0	0
Derivatives:
Foreign currency and cross-currency swap contracts	0	0
Significant unobservable inputs (Level 3) [Member] | Cross-currency swap contracts [Member]
Derivatives:
Foreign currency and cross-currency swap contracts	0	0
Derivatives:
Foreign currency and cross-currency swap contracts	0	0
Significant unobservable inputs (Level 3) [Member] | Interest rate swap contracts [Member]
Derivatives:
Interest rate swap contracts	0	0
Derivatives:
Interest rate swap contracts	0	0
U.S. Treasury notes [Member]
Assets:
Interest-bearing securities	16	47
U.S. Treasury notes [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]
Assets:
Interest-bearing securities	16	47
U.S. Treasury notes [Member] | Significant other observable inputs (Level 2) [Member]
Assets:
Interest-bearing securities	0	0
U.S. Treasury notes [Member] | Significant unobservable inputs (Level 3) [Member]
Assets:
Interest-bearing securities	0	0
U.S. Treasury bills [Member]
Assets:
Interest-bearing securities	0	1,400
U.S. Treasury bills [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]
Assets:
Interest-bearing securities	0	1,400
U.S. Treasury bills [Member] | Significant other observable inputs (Level 2) [Member]
Assets:
Interest-bearing securities	0	0
U.S. Treasury bills [Member] | Significant unobservable inputs (Level 3) [Member]
Assets:
Interest-bearing securities	0	0
Money market mutual funds [Member]
Assets:
Interest-bearing securities	5,837	5,856
Money market mutual funds [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]
Assets:
Interest-bearing securities	5,837	5,856
Money market mutual funds [Member] | Significant other observable inputs (Level 2) [Member]
Assets:
Interest-bearing securities	0	0
Money market mutual funds [Member] | Significant unobservable inputs (Level 3) [Member]
Assets:
Interest-bearing securities	0	0
Other short-term interest-bearing securities [Member]
Assets:
Interest-bearing securities	0	1
Other short-term interest-bearing securities [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]
Assets:
Interest-bearing securities	0	0
Other short-term interest-bearing securities [Member] | Significant other observable inputs (Level 2) [Member]
Assets:
Interest-bearing securities	0	1
Other short-term interest-bearing securities [Member] | Significant unobservable inputs (Level 3) [Member]
Assets:
Interest-bearing securities	$ 0	$ 0