Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12355-112629

Name:	us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Debt - December 2017 Senior Term Loan Credit Agreement Amendment - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	May 22, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Loss on extinguishment of debt		$ (1)	$ (32)	$ (32)
December 2017 Senior Term Loan Credit Agreement Amendment
Debt Instrument [Line Items]
Loss on extinguishment of debt	$ (1)