Retirement Benefit Plans , Fair Value Measurement (Details) $ in Millions	12 Months Ended
	Apr. 24, 2015 USD ($) fund	Apr. 25, 2014 USD ($)	Apr. 26, 2013 USD ($)
Absolute return strategy funds
Defined Benefit Plan Disclosure [Line items]
Number of funds | fund	2
Absolute return strategy funds in process of liquidation, fair value	$ 4
Absolute return strategy funds in process of liquidation, expected receipt of proceeds	5 years
Private equity fund
Defined Benefit Plan Disclosure [Line items]
Private equity funds, unfunded commitments	$ 59
Private equity funds, estimated minimum liquidation period	1 year
Private equity funds, estimated maximum liquidation period	15 years
U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	$ 2,204	$ 1,917	$ 1,717
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	959	851
Total realized gains included in income	162	23
Total unrealized (losses) gains included in accumulated other comprehensive loss	(130)	86
Purchases and sales, net	(318)	(1)
Ending balance	673	959
U.S. Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	356	390
U.S. Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	1,175	568
U.S. Pension Benefits | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	673	959
U.S. Pension Benefits | Short-term investments
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	247	157
U.S. Pension Benefits | Short-term investments | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	247	157
U.S. Pension Benefits | Short-term investments | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
U.S. Pension Benefits | Short-term investments | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
U.S. Pension Benefits | U.S. government securities
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	155	158
U.S. Pension Benefits | U.S. government securities | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	109	108
U.S. Pension Benefits | U.S. government securities | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	46	50
U.S. Pension Benefits | U.S. government securities | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
U.S. Pension Benefits | Corporate debt securities
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	5	60
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	1	1
Total realized gains included in income	0	0
Total unrealized (losses) gains included in accumulated other comprehensive loss	0	0
Purchases and sales, net	0	0
Ending balance	1	1
U.S. Pension Benefits | Corporate debt securities | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
U.S. Pension Benefits | Corporate debt securities | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	4	59
U.S. Pension Benefits | Corporate debt securities | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	1	1
U.S. Pension Benefits | Other common stock
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets		125
U.S. Pension Benefits | Other common stock | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets		125
U.S. Pension Benefits | Other common stock | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets		0
U.S. Pension Benefits | Other common stock | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets		0
U.S. Pension Benefits | Equity mutual funds/commingled trusts
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	951	578
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	285	227
Total realized gains included in income	65	0
Total unrealized (losses) gains included in accumulated other comprehensive loss	(31)	58
Purchases and sales, net	(119)	0
Ending balance	200	285
U.S. Pension Benefits | Equity mutual funds/commingled trusts | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
U.S. Pension Benefits | Equity mutual funds/commingled trusts | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	751	293
U.S. Pension Benefits | Equity mutual funds/commingled trusts | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	200	285
U.S. Pension Benefits | Fixed income mutual funds
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	374	166
U.S. Pension Benefits | Fixed income mutual funds | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
U.S. Pension Benefits | Fixed income mutual funds | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	374	166
U.S. Pension Benefits | Fixed income mutual funds | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
U.S. Pension Benefits | Partnership units
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	472	673
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	673	623
Total realized gains included in income	97	23
Total unrealized (losses) gains included in accumulated other comprehensive loss	(99)	28
Purchases and sales, net	(199)	(1)
Ending balance	472	673
U.S. Pension Benefits | Partnership units | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
U.S. Pension Benefits | Partnership units | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
U.S. Pension Benefits | Partnership units | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	472	673
Non-U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	1,189	889	$ 733
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	21	18
Total unrealized (losses) gains included in accumulated other comprehensive loss	1	1
Purchases and sales, net	63	1
Foreign currency exchange	(9)	1
Ending balance	76	21
Non-U.S. Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	1,113	868
Non-U.S. Pension Benefits | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	76	21
Non-U.S. Pension Benefits | Partnership units
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	16	10
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	10	8
Total unrealized (losses) gains included in accumulated other comprehensive loss	2	1
Purchases and sales, net	7	1
Foreign currency exchange	(3)	0
Ending balance	16	10
Non-U.S. Pension Benefits | Partnership units | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Partnership units | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Partnership units | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	16	10
Non-U.S. Pension Benefits | Registered investment companies
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	1,113	868
Non-U.S. Pension Benefits | Registered investment companies | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Registered investment companies | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	1,113	868
Non-U.S. Pension Benefits | Registered investment companies | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Insurance contracts
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	60	11
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	11	10
Total unrealized (losses) gains included in accumulated other comprehensive loss	(1)	0
Purchases and sales, net	56	0
Foreign currency exchange	(6)	1
Ending balance	60	11
Non-U.S. Pension Benefits | Insurance contracts | Level 1
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Insurance contracts | Level 2
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	0	0
Non-U.S. Pension Benefits | Insurance contracts | Level 3
Defined Benefit Plan Disclosure [Line items]
Fair value of plan assets	$ 60	$ 11
Minimum | Partnerships
Defined Benefit Plan Disclosure [Line items]
Range of notice period	45 days
Minimum | Real asset investments
Defined Benefit Plan Disclosure [Line items]
Real asset investments, estimated liquidation and redemption period	30 days
Maximum | Partnerships
Defined Benefit Plan Disclosure [Line items]
Range of notice period	95 days
Maximum | Real asset investments
Defined Benefit Plan Disclosure [Line items]
Real asset investments, estimated liquidation and redemption period	10 years