Financial Instruments (Tables)

9 Months Ended

Dec. 31, 2018

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, 2018		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	$	40,125	$	35,756	$	—	$	4,570	$	40,326

	Carrying amount at March 31, 2018		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	$	40,820	$	37,549	$	—	$	3,737	$	41,286