Pension Benefits (Summary Of Pension Plan Assets Using Fair Value Hierarchy By Asset Class) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014		Mar. 31, 2013
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	$ 298	$ 300		$ 290
United States [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	56	8
United States [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	18	19
United States [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	138	132
United States [Member] | Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	14	7
United States [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	14	22
United States [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	14	10
United States [Member] | Asset-backed Securities and Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	26	22
United States [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	63
United States [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	18	16
United States [Member] | Other Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Other funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Total [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets		299
United States [Member] | Receivable [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets		1	[1]
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	55	8
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	18	19
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Asset-backed Securities and Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Other Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Other funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 1 [Member] | Total [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	73	27
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	1	0
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	138	132
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	14	7
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	14	22
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	14	10
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities and Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	26	22
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	63
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Other Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Other funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 2 [Member] | Total [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	207	256
United States [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	18	16		14
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities and Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	18	16		14
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Other Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Other funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
United States [Member] | Fair Value, Inputs, Level 3 [Member] | Total [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	18	16
Foreign Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	612	590		135
Foreign Pension Plan, Defined Benefit [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	8	7
Foreign Pension Plan, Defined Benefit [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	156	163
Foreign Pension Plan, Defined Benefit [Member] | Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	79	4
Foreign Pension Plan, Defined Benefit [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	13	242
Foreign Pension Plan, Defined Benefit [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Asset-backed Securities and Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	191	45
Foreign Pension Plan, Defined Benefit [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	26	26
Foreign Pension Plan, Defined Benefit [Member] | Other Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	13	52
Foreign Pension Plan, Defined Benefit [Member] | Other funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	126	51
Foreign Pension Plan, Defined Benefit [Member] | Total [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets		590
Foreign Pension Plan, Defined Benefit [Member] | Receivable [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets		0	[1]
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	8	7
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	7	6
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	26	4
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	6
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Asset-backed Securities and Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	64	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Other Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	3
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Other funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	7	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Total [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	112	26
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	149	157
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	53	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	13	236
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities and Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	127	45
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	19
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Other Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	13	49
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Other funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	115	46
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | Total [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	470	552
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	30	12		5
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities and Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	26	7		5
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Other Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	0	0
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Other funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	4	5
Foreign Pension Plan, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Total [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Plan Assets	$ 30	$ 12

[1] Represents pending trades at March 31, 2014.