Stockholders' Equity (Details)				12 Months Ended
		Dec. 23, 2013 shares	Aug. 23, 2013 USD ($) shares	Jul. 31, 2016 USD ($) Period_of_time $ / shares shares	Jul. 31, 2015 USD ($) $ / shares shares	Jul. 31, 2014 USD ($) $ / shares shares	Aug. 31, 2016 $ / shares	Aug. 19, 2016 USD ($)	Jul. 31, 2016 USD ($) $ / shares shares	Jul. 31, 2015 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense				$ 281,000,000	$ 257,000,000	$ 204,000,000
Stockholders' Equity (Textuals)
Stock repurchases under stock repurchase programs				$ (2,264,000,000)	(1,245,000,000)	(1,577,000,000)
Common stock dividends, cash paid (per share) | $ / shares				$ 1.20
Dividends and dividend rights paid				$ (318,000,000)	$ (283,000,000)	$ (220,000,000)
Common stock, shares authorized (in shares) | shares									750,000,000	750,000,000
Pool shares reduced for each share granted | shares				2.3
Pool shares increased for each share forfeited | shares				2.3
Stock offering period, months, employee stock purchase plans				6 months
Stock accrual period, employee stock purchase plans, number of accrual periods | Period_of_time				2
Stock offering period, number of months in accrual period				3 months
Percentage of lower of the closing price for stock on the first day last day of the offering period				85.00%
Shares issued during period for Employee Stock Purchase Plans | shares				882,206	892,632	1,044,961
Shares available for issuance under Employee Stock Purchase Plan | shares									3,756,567
Share-based Compensation [Abstract]
Income tax benefit				$ (86,000,000)	$ (75,000,000)	$ (60,000,000)
Decrease in net income from continuing operations				$ 192,000,000	$ 167,000,000	$ 126,000,000
Share-Based Awards Available for Grant [Roll Forward]
Shares available for Grant, Beginning | shares				17,183,000	24,203,000	12,120,000
Additional shares authorized | shares						19,000,000
Options granted | shares				(2,553,000)	(1,981,000)	(2,206,000)
Restricted stock units granted | shares	[1]			(9,364,000)	(8,053,000)	(8,959,000)
Share-based awards canceled/forfeited/expired | shares	[1],[2]			3,724,000	3,014,000	4,248,000
Shares available for Grant, Ending | shares				8,990,000	17,183,000	24,203,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of shares, Beginning Balance | shares				8,713,000	10,938,000	14,206,000
Number of shares, Granted | shares				2,553,000	1,981,000	2,206,000
Number of shares, Assumed in connection with acquisitions | shares						261,000
Number of shares, Exercised | shares				(2,566,000)	(3,704,000)	(5,041,000)
Number of shares, Canceled or expired | shares				(354,000)	(502,000)	(694,000)
Number of shares, Ending Balance | shares				8,346,000	8,713,000	10,938,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price per share, Beginning Balance | $ / shares				$ 69.13	$ 52.67	$ 43.77
Granted (in usd per share) | $ / shares				113.08	106.86	82.15
Assumed in connection with acquisitions (in usd per share) | $ / shares						5.16
Exercised (in usd per share) | $ / shares				48.93	41.65	37.74
Canceled or expired (in usd per share) | $ / shares				74.56	62.32	54.77
Weighted average exercise price per share, Ending Balance | $ / shares				$ 88.55	$ 69.13	$ 52.67
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Number of shares (in thousands), options outstanding | shares				8,713,000	10,938,000	14,206,000			8,346,000	8,713,000
Weighted average remaining contractual life (in years), options outstanding				6 years 25 days
Weighted average exercise price per share, options outstanding | $ / shares				$ 69.13	$ 52.67	$ 43.77			$ 88.55	$ 69.13
Aggregate intrinsic value (in millions), options outstanding									$ 206,000,000
Number of shares (in thousands), options exercisable and expected to vest | shares									7,693,000
Weighted average remaining contractual life (in years), options exercisable and expected to vest				5 years 10 months 20 days
Weighted Average Exercise Price per Share. options exercisable and expected to vest | $ / shares									$ 86.76
Aggregate Intrinsic Value (in millions), options exercisable and expected to vest									$ 203,000,000
Number of Shares (in thousands), options exercisable | shares									3,757,000
Weighted Average Remaining Contractual Life (in Years), options exercisable				3 years 9 months 22 days
Weighted Average Exercise Price per Share, options exercisable | $ / shares									$ 68.38
Aggregate Intrinsic Value (in millions), options exercisable									$ 168,000,000
Additional information regarding stock options, restricted stock and ESPP
Weighted average fair value of options granted (per share) | $ / shares				$ 20.35	$ 19.39	$ 21.34
Total grant date fair value of options vested				$ 32,000,000	$ 36,000,000	$ 28,000,000
Aggregate intrinsic value of options exercised				134,000,000	191,000,000	177,000,000
Total tax benefit for stock option and ESPP share-based compensation				86,000,000	75,000,000	60,000,000
Cash received from option exercises				126,000,000	154,000,000	190,000,000
Cash tax benefits realized related to tax deductions for non-qualified option exercises and disqualifying dispositions under all share-based payment arrangements				$ 47,000,000	$ 68,000,000	$ 63,000,000
Summary of restricted stock unit activity
Nonvested, Number of shares, Beginning Balance | shares				8,916,000	9,455,000	9,184,000
Number of shares, Granted | shares				4,072,000	3,501,000	3,896,000
Number of shares, Assumed in connection with acquisitions | shares					292,000	782,000
Number of shares, Vested | shares				(2,392,000)	(3,155,000)	(2,820,000)
Number of shares, Forfeited | shares				(1,557,000)	(1,177,000)	(1,587,000)
Nonvested, Number of shares, Ending Balance | shares				9,039,000	8,916,000	9,455,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Nonvested, Weighted Average Grant Date Fair Value per share, Beginning Balance | $ / shares				$ 72.48	$ 62.46	$ 55.23
Granted (in usd per share) | $ / shares				99.30	89.58	71.37
Assumed or granted in connection with acquisitions (in usd per share) | $ / shares					91.87	71.00
Vested (in usd per share) | $ / shares				78.07	67.00	53.98
Forfeited (in usd per share) | $ / shares				77.03	62.32	61.76
Nonvested, Weighted Average Grant Date Fair Value per share, Ending Balance | $ / shares				$ 82.30	$ 72.48	$ 62.46
Additional information regarding RSUs
Total tax benefit related to RSU share-based compensation expense				$ 86,000,000	$ 75,000,000	$ 60,000,000
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income (loss), net of tax									(32,000,000)	$ (30,000,000)
Computer software
Share-based Compensation [Abstract]
Share-based compensation expense				6,000,000
Subsequent Event
Stockholders' Equity (Textuals)
Stock repurchase program, authorized amount								$ 2,000,000,000
Dividend per share payable (in usd per share) | $ / shares							$ 0.34
Discontinued Operations, Disposed of by Sale
Additional information regarding stock options, restricted stock and ESPP
Share-based compensation expense for stock options and ESPP				3,000,000	15,000,000	18,000,000
Additional information regarding RSUs
Share-based compensation for RSUs				3,000,000	15,000,000	18,000,000
Cost of service and other revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense				8,000,000	6,000,000	7,000,000
Selling and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense				77,000,000	69,000,000	53,000,000
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense				90,000,000	80,000,000	59,000,000
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense				103,000,000	87,000,000	67,000,000
Segment, Continuing Operations
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense				$ 278,000,000	$ 242,000,000	$ 186,000,000
Stock Options
Stockholders' Equity (Textuals)
Award vesting period (in years)				3 years
Number of years until options vest				7 years
Unrecognized compensation cost related to non-vested share based compensation expense									75,000,000
Expected weighted average vesting period to recognize compensation cost related to share based compensation expense, in years				2 years 5 months
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Weighted average expected volatility				22.00%	23.00%	23.00%
Share-Based Awards Available for Grant [Roll Forward]
Shares available for Grant, Ending | shares				9,000,000
Restricted Stock Units (RSUs)
Stockholders' Equity (Textuals)
Award vesting period (in years)				3 years
Unrecognized compensation cost related to non-vested share based compensation expense									$ 510,000,000
Expected weighted average vesting period to recognize compensation cost related to share based compensation expense, in years				2 years 5 months
Share-based Compensation [Abstract]
Income tax benefit				$ (73,000,000)	$ (64,000,000)	$ (49,000,000)
Additional information regarding stock options, restricted stock and ESPP
Share-based compensation expense for stock options and ESPP				230,000,000	194,000,000	143,000,000
Total tax benefit for stock option and ESPP share-based compensation				73,000,000	64,000,000	49,000,000
Additional information regarding RSUs
Total fair market value of shares vested				288,000,000	282,000,000	204,000,000
Share-based compensation for RSUs				230,000,000	194,000,000	143,000,000
Total tax benefit related to RSU share-based compensation expense				73,000,000	64,000,000	49,000,000
Cash tax benefits realized for tax deductions for RSUs				$ 92,000,000	$ 96,000,000	$ 134,000,000
Employee Stock
Stockholders' Equity (Textuals)
Common stock, shares authorized (in shares) | shares									23,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Weighted average expected volatility				25.00%	21.00%	21.00%
Share Based Compensation Expense
Decrease in net income per share from continuing operations:
Basic (in usd per share) | $ / shares				$ 0.73	$ 0.59	$ 0.44
Diluted (in usd per share) | $ / shares				$ 0.72	$ 0.58	$ 0.43
Stock Options And Espp
Share-based Compensation [Abstract]
Income tax benefit				$ (13,000,000)	$ (11,000,000)	$ (11,000,000)
Additional information regarding stock options, restricted stock and ESPP
Share-based compensation expense for stock options and ESPP				48,000,000	48,000,000	43,000,000
Total tax benefit for stock option and ESPP share-based compensation				13,000,000	11,000,000	11,000,000
Additional information regarding RSUs
Share-based compensation for RSUs				48,000,000	48,000,000	43,000,000
Total tax benefit related to RSU share-based compensation expense				$ 13,000,000	$ 11,000,000	$ 11,000,000
Common Stock
Stockholders' Equity (Textuals)
Common stock repurchased (in shares) | shares				24,816,000	13,809,000	22,467,000
Accumulated Net Unrealized Investment Gain (Loss) | Debt Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income (loss), net of tax									$ 1,000,000	0
Accumulated Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income (loss), net of tax									$ (33,000,000)	$ (30,000,000)
Minimum | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected volatility (range)				22.00%	22.00%	22.00%
Risk-free interest rate (range)				0.98%	1.13%	1.01%
Expected dividend yield				1.06%	0.93%	0.92%
Minimum | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected volatility (range)				23.00%	20.00%	19.00%
Risk-free interest rate (range)				0.06%	0.01%	0.02%
Expected dividend yield				1.13%	0.96%	0.94%
Maximum
Stockholders' Equity (Textuals)
Market price of common stock used to define in money options exercise price | $ / shares									$ 110.99
Maximum | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected volatility (range)				26.00%	24.00%	24.00%
Risk-free interest rate (range)				1.49%	1.47%	1.40%
Expected dividend yield				1.36%	1.05%	1.06%
Maximum | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected volatility (range)				26.00%	23.00%	22.00%
Risk-free interest rate (range)				0.47%	0.15%	0.08%
Expected dividend yield				1.34%	1.19%	1.15%
Restated 2005 Plan | Stock Options
Stockholders' Equity (Textuals)
Pool shares reduced for each share granted | shares				1
Number of shares added back to plan when grants are forfeited | shares				1
Current Program
Stockholders' Equity (Textuals)
Stock repurchase program remaining authorized repurchase amount									$ 360,000,000
Restated 2005 Plan
Stockholders' Equity (Textuals)
Common stock, shares authorized (in shares) | shares									115,000,000
Common Stock | Accelerated Stock Repurchase Agreement
Stockholders' Equity (Textuals)
Common stock repurchased (in shares) | shares		2,600,000.0	17,600,000.0
Stock repurchase program, authorized amount			$ 1,400,000,000.0
Accelerated share repurchases, settlement (payment) or receipt			$ 1,400,000,000

[1] RSUs granted from the pool of shares available for grant under our 2005 Equity Incentive Plan reduce the pool by 2.3 shares for each share granted. RSUs forfeited and returned to the pool of shares available for grant increase the pool by 2.3 shares for each share forfeited.

[2] Stock options and restricted stock units canceled, expired or forfeited under our 2005 Equity Incentive Plan are returned to the pool of shares available for grant. Stock options and restricted stock units canceled, expired or forfeited under older expired plans are not returned to the pool of shares available for grant.