Goodwill, Customer Relationships and Other Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 20,674		$ 20,674	$ 21,627
Discount rate (percent)			6.00%
Fair value inputs after tax cost of debt rate (percent)	3.40%		3.40%
Fair value inputs cost of equity rate (percent)	8.30%		8.30%
Percentage of reasonable implied control premium (percent)	18.40%		18.40%
Impairment	0	1,100	1,092	0	0
Consumer
Finite-Lived Intangible Assets [Line Items]
Goodwill	10,348		10,348	10,348
Impairment			0
Business
Finite-Lived Intangible Assets [Line Items]
Goodwill	6,363		6,363	6,363
Impairment			0
Wholesale
Finite-Lived Intangible Assets [Line Items]
Goodwill	3,274		3,274	3,274
Impairment			0
Data hosting
Finite-Lived Intangible Assets [Line Items]
Goodwill	689		689	1,642
Discount rate (percent)			11.00%
Fair value inputs after tax cost of debt rate (percent)	3.40%		3.40%
Fair value inputs cost of equity rate (percent)	11.90%		11.90%
Impairment			$ 1,092