Financial Instruments (Tables)

9 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of carrying amount and estimated fair values of our exchangeable notes as well as current and long-term debt

The following table presents carrying amounts and estimated fair values of current and long-term debt and financing obligations:

	Carrying amount at December 31, 2017		Estimated Fair Value Using Input Type
			Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
Current and long-term debt and financing obligations	$	36,690	$	30,281	$	2,970	$	4,954	$	38,205

	Carrying amount at March 31, 2017		Estimated Fair Value Using Input Type
			Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
Current and long-term debt and financing obligations	$	40,581	$	33,196	$	4,352	$	5,468	$	43,016