Amount of cash receipt from (payment to) bank; or stock received from (issuance to) bank in the settlement of the accelerated share repurchase agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 25
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6405686&loc=d3e22802-112653

Name:	us-gaap_AcceleratedShareRepurchasesSettlementPaymentOrReceipt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Subsequent Event - Additional Information (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Jan. 04, 2018
Subsequent Event [Line Items]
Accelerated share repurchase contract amount		$ 200
Scenario, Forecast
Subsequent Event [Line Items]
Accelerated share repurchases received	4.1
Subsequent Event
Subsequent Event [Line Items]
Accelerated share repurchases paid to bank			$ (200)