Financial Instruments (Tables)

3 Months Ended

Jun. 30, 2015

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 June 30, 2015		Estimated Fair Value Using Input Type
			Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
Current and long-term debt	$	33,759	$	26,216	$	4,885	$	1,756	$	32,857

	Carrying amount at March 31, 2015		Estimated Fair Value Using Input Type
			Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
Current and long-term debt	$	33,434	$	27,238	$	4,906	$	1,410	$	33,554