Financial Instruments (Tables)

6 Months Ended

Sep. 30, 2016

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:

	Carrying amount at September 30, 2016		Estimated Fair Value Using Input Type
			Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
Current and long-term debt	$	35,945	$	26,735	$	4,697	$	5,032	$	36,464

	Carrying amount at March 31, 2016		Estimated Fair Value Using Input Type
			Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
Current and long-term debt	$	33,645	$	21,757	$	4,474	$	2,130	$	28,361