Earnings per Share (Antidilutive Shares) (Details) - shares shares in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Anti-dilutive potential shares due to net loss	250	166	250	71

Antidilutive Securities Excluded from Computation of Earnings-per-Share Due to Net Loss, Amount

No definition available.

Name:	wft_AntidilutiveSecuritiesExcludedfromComputationofEarningsperShareDuetoNetLossAmount
Namespace Prefix:	wft_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration