Stockholders' Equity (Other Comprehensive Income (Loss), Net of Tax) (Details) - USD ($) $ in Millions		3 Months Ended
		Jun. 30, 2015	Jun. 30, 2014
Equity [Abstract]
Foreign currency translation adjustments arising during period, net of income tax expense of nil and nil (1)	[1]	$ 347	$ 98
Reclassified to income statement, net of income tax expense of nil and nil		0	0
Unrealized gains (losses) on cash flow hedges arising during period, net of income tax expense of nil and nil		4	(2)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax		(29)	0
Amortization of actuarial loss and prior service costs, net of income tax expense of $4 and $1 (3)	[2]	7	3
Foreign currency translation adjustments, net of income tax expense of nil and nil		(6)	(1)
Other comprehensive income (loss), pension and other postretirement benefit plans, adjustment, net of tax		(28)	2
Other comprehensive income (loss), net of tax		323	98
Foreign currency translation adjustments arising during period, net of income tax expense of nil and nil		0	0
Other comprehensive income (Loss), foreign currency transaction and translation reclassification adjustment from AOCI, realized upon sale or liquidation, tax		0	0
Other comprehensive income (Loss), unrealized gain (Loss) on derivatives arising during period, net of tax		0	0
Other comprehensive (Income) loss, pension and other postretirement benefit plans, net prior service cost (Credit), tax		8	0
Amortization of actuarial loss and prior service costs, net of income tax expense of $4 and $1		4	1
Foreign currency translation adjustments, net of income tax expense of nil and nil		$ 0	$ 0

[1] The first quarters of 2016 and 2015 include net foreign currency translation gains of $50 million and net foreign currency translation losses of $12 million attributable to noncontrolling and redeemable noncontrolling interests.

[2] Pre-tax amount reclassified into cost of sales and operating expenses in our condensed consolidated statements of operations. The related tax expense was reclassified into income tax expense in our condensed consolidated statements of operations.