Retirement Benefit Plans, Fair Value Measurement (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Apr. 27, 2012	Apr. 29, 2011	Apr. 30, 2010
Partnerships
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Range of notice period	from 45 to 95 days
Absolute Return Strategy Funds
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Investments at fair value	$ 12
Private Equity Fund
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Unfunded commitments	21
Real Asset Investments
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Estimated minimum liquidation period	1 year
Estimated maximum liquidation period	15 years
U.S. Pension Benefits
Defined Benefit Plan Disclosure
Fair value of plan assets	1,470	1,392	1,104
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	685	601
Realized gains/(losses) and other-than-temporary impairment losses included in earnings	17	5
Unrealized gains included in accumulated other comprehensive loss	(17)	78
Purchases, issuances and settlements	67	1
Balance as of	752	685
U.S. Pension Benefits | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	470	461
U.S. Pension Benefits | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	248	246
U.S. Pension Benefits | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	752	685
U.S. Pension Benefits | Short-term Investments
Defined Benefit Plan Disclosure
Fair value of plan assets	133	186
U.S. Pension Benefits | Short-term Investments | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	133	186
U.S. Pension Benefits | Short-term Investments | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | Short-term Investments | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | U.S. Government Securities
Defined Benefit Plan Disclosure
Fair value of plan assets	169	118
U.S. Pension Benefits | U.S. Government Securities | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	151	74
U.S. Pension Benefits | U.S. Government Securities | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	18	44
U.S. Pension Benefits | U.S. Government Securities | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | Corporate Debt Securities
Defined Benefit Plan Disclosure
Fair value of plan assets	46	82
U.S. Pension Benefits | Corporate Debt Securities | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | Corporate Debt Securities | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	45	82
U.S. Pension Benefits | Corporate Debt Securities | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	1	0
U.S. Pension Benefits | Other Common Stock
Defined Benefit Plan Disclosure
Fair value of plan assets	186	201
U.S. Pension Benefits | Other Common Stock | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	186	201
U.S. Pension Benefits | Other Common Stock | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | Other Common Stock | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | Equity Mutual Funds/Commingled Trusts
Defined Benefit Plan Disclosure
Fair value of plan assets	316	309
U.S. Pension Benefits | Equity Mutual Funds/Commingled Trusts | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | Equity Mutual Funds/Commingled Trusts | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	123	67
U.S. Pension Benefits | Equity Mutual Funds/Commingled Trusts | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	193	242
U.S. Pension Benefits | Fixed Income Mutual Funds
Defined Benefit Plan Disclosure
Fair value of plan assets	62	53
U.S. Pension Benefits | Fixed Income Mutual Funds | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | Fixed Income Mutual Funds | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	62	53
U.S. Pension Benefits | Fixed Income Mutual Funds | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | Partnership Units
Defined Benefit Plan Disclosure
Fair value of plan assets	558	443
U.S. Pension Benefits | Partnership Units | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | Partnership Units | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
U.S. Pension Benefits | Partnership Units | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	558	443
Non-U.S. Pension Benefits
Defined Benefit Plan Disclosure
Fair value of plan assets	638	606	420
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	16	7
Foreign currency exchange	(2)	1
Purchases, issuances and settlements	2	8
Balance as of	16	16
Non-U.S. Pension Benefits | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	622	590
Non-U.S. Pension Benefits | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	16	16
Non-U.S. Pension Benefits | Partnership Units
Defined Benefit Plan Disclosure
Fair value of plan assets	7	7
Non-U.S. Pension Benefits | Partnership Units | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Partnership Units | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Partnership Units | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	7	7
Non-U.S. Pension Benefits | Registered Investment Companies
Defined Benefit Plan Disclosure
Fair value of plan assets	622	590
Non-U.S. Pension Benefits | Registered Investment Companies | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Registered Investment Companies | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	622	590
Non-U.S. Pension Benefits | Registered Investment Companies | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Insurance Contracts
Defined Benefit Plan Disclosure
Fair value of plan assets	9	9
Non-U.S. Pension Benefits | Insurance Contracts | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Insurance Contracts | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Insurance Contracts | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	9	9
Post-Retirement Benefits
Defined Benefit Plan Disclosure
Fair value of plan assets	204	198	158
Other items to reconcile to fair value of plan assts	(8)	(9)
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	102	89
Realized gains/(losses) and other-than-temporary impairment losses included in earnings	2	1
Unrealized gains included in accumulated other comprehensive loss	(2)	12
Purchases, issuances and settlements	6	0
Balance as of	108	102
Post-Retirement Benefits | Short-term Investments
Defined Benefit Plan Disclosure
Fair value of plan assets	19	28
Post-Retirement Benefits | Short-term Investments | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	19	28
Post-Retirement Benefits | Short-term Investments | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Short-term Investments | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | U.S. Government Securities
Defined Benefit Plan Disclosure
Fair value of plan assets	25	17
Post-Retirement Benefits | U.S. Government Securities | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	22	11
Post-Retirement Benefits | U.S. Government Securities | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	3	6
Post-Retirement Benefits | U.S. Government Securities | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Corporate Debt Securities
Defined Benefit Plan Disclosure
Fair value of plan assets	6	12
Post-Retirement Benefits | Corporate Debt Securities | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Corporate Debt Securities | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	6	12
Post-Retirement Benefits | Corporate Debt Securities | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Other Common Stock
Defined Benefit Plan Disclosure
Fair value of plan assets	27	30
Post-Retirement Benefits | Other Common Stock | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	27	30
Post-Retirement Benefits | Other Common Stock | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Other Common Stock | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Equity Mutual Funds/Commingled Trusts
Defined Benefit Plan Disclosure
Fair value of plan assets	46	46
Post-Retirement Benefits | Equity Mutual Funds/Commingled Trusts | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Equity Mutual Funds/Commingled Trusts | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	18	10
Post-Retirement Benefits | Equity Mutual Funds/Commingled Trusts | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	28	36
Post-Retirement Benefits | Fixed Income Mutual Funds
Defined Benefit Plan Disclosure
Fair value of plan assets	9	8
Post-Retirement Benefits | Fixed Income Mutual Funds | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Fixed Income Mutual Funds | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	9	8
Post-Retirement Benefits | Fixed Income Mutual Funds | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Partnership Units
Defined Benefit Plan Disclosure
Fair value of plan assets	80	66
Post-Retirement Benefits | Partnership Units | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Partnership Units | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Post-Retirement Benefits | Partnership Units | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	80	66
Post-Retirement Benefits | Fair Value of Plan Assets before Reconciling Items
Defined Benefit Plan Disclosure
Fair value of plan assets	212	207
Post-Retirement Benefits | Fair Value of Plan Assets before Reconciling Items | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	68	69
Post-Retirement Benefits | Fair Value of Plan Assets before Reconciling Items | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	36	36
Post-Retirement Benefits | Fair Value of Plan Assets before Reconciling Items | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	$ 108	$ 102