OPERATING ASSETS AND LIABILITIES - INVENTORIES - Narrative (Details)	Dec. 31, 2017
Subclassifications of assets, liabilities and equities [abstract]
Indirect production costs (as a percent of net inventory value)	50.00%

Current Inventories, Indirect Production Costs, Percent Of Inventory Value, Approximate

No definition available.

Name:	nvo_CurrentInventoriesIndirectProductionCostsPercentOfInventoryValueApproximate
Namespace Prefix:	nvo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant