Debt (Interest Rate Swaps) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Mark-to-market adjustments	$ 0.6nwl_DebtMarkToMarketAdjustment		$ 11.8nwl_DebtMarkToMarketAdjustment
Reduction of interest expense	3.4	3.6
Interest Rate Swaps [Member]
Principal amount of note	$ 596.0

Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant