Retirement Benefit Plans , Fair Value Measurement (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Apr. 26, 2013	Apr. 27, 2012	Apr. 29, 2011
Partnership Units
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	$ 8	$ 7
Insurance Contracts
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	10	9
Partnerships | Minimum
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Range of notice period	45 days
Partnerships | Maximum
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Range of notice period	95 days
Absolute Return Strategy Funds
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Number of funds	2
Investments at fair value	7
Partnership Exit, Expected Term of Distribution Payments	5 years
Private Equity Fund
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Unfunded commitments	29
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
Real Asset Investments | Minimum
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Estimated liquidation and redemption period	30 days
Real Asset Investments | Maximum
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Estimated liquidation and redemption period	10 years
U.S. Pension Benefits
Defined Benefit Plan Disclosure
Fair value of plan assets	1,717	1,470	1,392
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	752	685
Realized gains/(losses) and other-than-temporary impairment losses included in earnings	8	17
Total unrealized gains (losses) included in accumulated other comprehensive loss	62	(17)
Purchases and sales, net	29	67
Balance as of	851	752
U.S. Pension Benefits | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	556	470
U.S. Pension Benefits | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	310	248
U.S. Pension Benefits | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	851	752
U.S. Pension Benefits | Short-term Investments
Defined Benefit Plan Disclosure
Fair value of plan assets	195	133
U.S. Pension Benefits | Short-term Investments | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	195	133
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	172	169
U.S. Pension Benefits | U.S. Government Securities | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	145	151
U.S. Pension Benefits | U.S. Government Securities | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	27	18
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	62	46
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	1	0
Realized gains/(losses) and other-than-temporary impairment losses included in earnings	0	0
Total unrealized gains (losses) included in accumulated other comprehensive loss	0	0
Purchases and sales, net	0	1
Balance as of	1	1
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	61	45
U.S. Pension Benefits | Corporate Debt Securities | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	1	1
U.S. Pension Benefits | Other Common Stock
Defined Benefit Plan Disclosure
Fair value of plan assets	216	186
U.S. Pension Benefits | Other Common Stock | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	216	186
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	377	316
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	193	242
Realized gains/(losses) and other-than-temporary impairment losses included in earnings	0	17
Total unrealized gains (losses) included in accumulated other comprehensive loss	34	(13)
Purchases and sales, net	0	(53)
Balance as of	227	193
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	150	123
U.S. Pension Benefits | Equity Mutual Funds/Commingled Trusts | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	227	193
U.S. Pension Benefits | Fixed Income Mutual Funds
Defined Benefit Plan Disclosure
Fair value of plan assets	72	62
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	72	62
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	623	558
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	558	443
Realized gains/(losses) and other-than-temporary impairment losses included in earnings	8	0
Total unrealized gains (losses) included in accumulated other comprehensive loss	28	(4)
Purchases and sales, net	29	119
Balance as of	623	558
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	623	558
Non-U.S. Pension Benefits
Defined Benefit Plan Disclosure
Fair value of plan assets	733	638	606
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	16	16
Total unrealized gains (losses) included in accumulated other comprehensive loss	1
Purchases and sales, net	1	2
Foreign currency exchange		(2)
Balance as of	18	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	715	622
Non-U.S. Pension Benefits | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	18	16
Non-U.S. Pension Benefits | Partnership Units
Defined Benefit Plan Disclosure
Fair value of plan assets	8	7
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of		7
Total unrealized gains (losses) included in accumulated other comprehensive loss		(1)
Purchases and sales, net		0
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	8	7
Non-U.S. Pension Benefits | Registered Investment Companies
Defined Benefit Plan Disclosure
Fair value of plan assets	715	622
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	715	622
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	10	9
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of		9
Total unrealized gains (losses) included in accumulated other comprehensive loss		0
Purchases and sales, net		1
Foreign currency exchange		(1)
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	10	9
Post-Retirement Benefits
Defined Benefit Plan Disclosure
Fair value of plan assets	233	204	198
Other items to reconcile to fair value of plan assts	(10)	(8)
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	108	102
Realized gains/(losses) and other-than-temporary impairment losses included in earnings	5	2
Total unrealized gains (losses) included in accumulated other comprehensive loss	4	(2)
Purchases and sales, net	3	6
Balance as of	120	108
Post-Retirement Benefits | Short-term Investments
Defined Benefit Plan Disclosure
Fair value of plan assets	28	32
Post-Retirement Benefits | Short-term Investments | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	28	19
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	24	25
Post-Retirement Benefits | U.S. Government Securities | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	20	22
Post-Retirement Benefits | U.S. Government Securities | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	4	3
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	9	6
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	9	6
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	31	27
Post-Retirement Benefits | Other Common Stock | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	31	27
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	53	46
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	28	36
Realized gains/(losses) and other-than-temporary impairment losses included in earnings	4	2
Total unrealized gains (losses) included in accumulated other comprehensive loss	0	(1)
Purchases and sales, net	0	(9)
Balance as of	32	28
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	21	18
Post-Retirement Benefits | Equity Mutual Funds/Commingled Trusts | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	19	28
Post-Retirement Benefits | Fixed Income Mutual Funds
Defined Benefit Plan Disclosure
Fair value of plan assets	10	9
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	10	9
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	88	80
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Balance as of	80	66
Realized gains/(losses) and other-than-temporary impairment losses included in earnings	1	0
Total unrealized gains (losses) included in accumulated other comprehensive loss	4	(1)
Purchases and sales, net	3	15
Balance as of	88	80
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	88	80
Post-Retirement Benefits | Fair Value of Plan Assets before Reconciling Items
Defined Benefit Plan Disclosure
Fair value of plan assets	243	212
Post-Retirement Benefits | Fair Value of Plan Assets before Reconciling Items | Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	79	68
Post-Retirement Benefits | Fair Value of Plan Assets before Reconciling Items | Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	44	36
Post-Retirement Benefits | Fair Value of Plan Assets before Reconciling Items | Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	$ 120	$ 108