Commitments and contingencies - Contractual obligations (Details) € in Millions	Dec. 31, 2017 EUR (€)
Contractual obligations
Purchase obligations	€ 2,526
Operating leases	961
Total contractual obligations	3,487
Within 1 year
Contractual obligations
Purchase obligations	1,983
Operating leases	255
Total contractual obligations	2,238
1 to 3 years
Contractual obligations
Purchase obligations	471
Operating leases	335
Total contractual obligations	806
4 to 5 years
Contractual obligations
Purchase obligations	67
Operating leases	185
Total contractual obligations	252
More than 5 years
Contractual obligations
Purchase obligations	5
Operating leases	186
Total contractual obligations	€ 191

The amount of future minimum lease payments payable under non-cancellable operating leases. Minimum lease payments are payments over the lease term that the lessee is or can be required to make, excluding contingent rent, costs for services and taxes to be paid by, and reimbursed to, the lessor, together with: (a) for a lessee, any amounts guaranteed by the lessee or by a party related to the lessee; or (b) for a lessor, any residual value guaranteed to the lessor by: (i) the lessee; (ii) a party related to the lessee; or (iii) a third party unrelated to the lessor that is financially capable of discharging the obligations under the guarantee.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2019-01-01
-Name IAS
-Number 17
-IssueDate 2017-01-01
-Paragraph 35
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=17&date=2017-03-02&anchor=para_35_a&doctype=Standard&book=B
-URIDate 2017-03-09

Name:	ifrs-full_MinimumLeasePaymentsPayableUnderNoncancellableOperatingLease
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant