Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 segment	Jun. 30, 2012
Segment information
Expenses	$ 3,810	$ 3,955	$ 7,541	$ 7,911
OPERATING INCOME	715	657	1,497	1,311
Number of operating segments			4
Operating segments
Segment information
Revenues	4,276	4,346	8,532	8,690
Expenses	2,062	2,063	4,007	4,083
OPERATING INCOME	2,214	2,283	4,525	4,607
Margin percentage	51.80%	52.50%	53.00%	53.00%
Consumer
Segment information
Revenues	1,494	1,540	3,005	3,104
Expenses	551	568	1,077	1,135
OPERATING INCOME	943	972	1,928	1,969
Margin percentage	63.10%	63.10%	64.20%	63.40%
Business
Segment information
Revenues	1,525	1,537	3,029	3,045
Expenses	937	943	1,818	1,853
OPERATING INCOME	588	594	1,211	1,192
Margin percentage	38.60%	38.60%	40.00%	39.10%
Wholesale
Segment information
Revenues	910	946	1,817	1,908
Expenses	301	313	575	625
OPERATING INCOME	609	633	1,242	1,283
Margin percentage	66.90%	66.90%	68.40%	67.20%
Data Hosting
Segment information
Revenues	347	323	681	633
Expenses	273	239	537	470
OPERATING INCOME	$ 74	$ 84	$ 144	$ 163
Margin percentage	21.30%	26.00%	21.10%	25.80%