Income Taxes 6 (Details) BRL in Millions, $ in Millions	1 Months Ended	12 Months Ended
	Nov. 30, 2013 BRL	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)
Income Tax Disclosure [Abstract]
Total deferred tax assets, net of valuation allowance		$ 600	$ 519
U.S. federal, state and foreign net operating loss carryforwards		671	542
Net operating loss carryforwards subject to expiration		$ 497
Net operating loss carryforwards expiration period		between 2016 and 2035
Net operating loss carryforwards not subject to expiration		$ 174
Change in valuation allowance		11	(2)
Unremitted earnings of foreign subsidiaries		$ 2,987	2,759
Determination of tax on unremitted foreign earnings is not practicable		It is not practicable to determine the amount of tax associated with such unremitted earnings.
Liability for uncertain tax positions, Gross		$ 163	162
Liability for uncertain tax positions, Current		1	3
Deferred tax assets related to uncertain tax positions		17	16
Unrecognized tax benefits that would affect effective tax rate		119	109
Amount of interest and penalties accrued		20	28
Decrease in amount of interest and penalties		$ (8)	$ (4)
Period of unrecognized tax benefit adjustment (in months)		12 months
Brazilian Tax Authority
Income Tax Examination [Line Items]
Tax assessment including interest and penalties	BRL 211	$ 59