Derivative Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2017	Jun. 30, 2016
Cash Flow Hedging [Member]
Derivative
Gain (Loss) on Foreign Currency Derivatives Recorded in Earnings, Net	$ 17	$ 6
Designated as Hedging Instrument [Member]
Derivative
Maximum Remaining Maturity of Foreign Currency Derivatives	18 months
Not Designated as Hedging Instrument [Member]
Derivative
Maximum Remaining Maturity of Foreign Currency Derivatives	3 months

Aggregate impact of foreign currency derivatives on earnings for the period. Includes impact of foreign currency cash flow hedge ineffectiveness and the ineffectiveness of fair value hedging derivatives and full change in fair value of the foreign currency derivatives not designated as hedging instruments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624177-113959

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