Goodwill, Capitalized Software and Other Intangible Assets 3 (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Mar. 31, 2013
Goodwill activity by segment
Balance at March 31, 2013	$ 5,871
Revision to purchase price allocation of prior year acquisition	(9)
Balance at March 31, 2013 as revised		5,862
Acquisitions	54
Balance at June 30, 2013	5,916
Mainframe Solutions [Member]
Goodwill activity by segment
Balance at March 31, 2013	4,178
Revision to purchase price allocation of prior year acquisition	0
Balance at March 31, 2013 as revised		4,178
Acquisitions	0
Balance at June 30, 2013	4,178
Enterprise Solutions [Member]
Goodwill activity by segment
Balance at March 31, 2013	1,612
Revision to purchase price allocation of prior year acquisition	(9)
Balance at March 31, 2013 as revised		1,603
Acquisitions	54
Balance at June 30, 2013	1,657
Services [Member]
Goodwill activity by segment
Balance at March 31, 2013	81
Revision to purchase price allocation of prior year acquisition	0
Balance at March 31, 2013 as revised		81
Acquisitions	0
Balance at June 30, 2013	$ 81