Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2017	Oct. 31, 2012	Jul. 31, 2012
Goodwill
Balance at beginning of period	$ 24,178
Goodwill acquired during the period	76
Changes due to foreign currency	(1)
Goodwill adjustments	(1)
Balance at end of period	24,252
Accumulated impairment losses		$ 13,700
Enterprise Group
Goodwill
Balance at beginning of period	15,945
Goodwill acquired during the period	76
Changes due to foreign currency	(1)
Goodwill adjustments	(1)
Balance at end of period	16,019
Enterprise Services
Goodwill
Balance at beginning of period	0
Goodwill acquired during the period	0
Changes due to foreign currency	0
Goodwill adjustments	0
Balance at end of period	0
Accumulated impairment losses			$ 8,000
Software
Goodwill
Balance at beginning of period	8,089
Goodwill acquired during the period	0
Changes due to foreign currency	0
Goodwill adjustments	0
Balance at end of period	8,089
Accumulated impairment losses		$ 5,700
Financial Services
Goodwill
Balance at beginning of period	144
Goodwill acquired during the period	0
Changes due to foreign currency	0
Goodwill adjustments	0
Balance at end of period	$ 144