Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 segment	Sep. 30, 2012
Segment information
Number of operating segments (segments)			4
Expenses	$ 5,200	$ 3,835	$ 12,741	$ 11,746
OPERATING (LOSS) INCOME	(685)	736	812	2,047
Operating segments
Segment information
Revenues	4,267	4,314	12,799	13,004
Expenses	2,105	2,071	6,112	6,154
OPERATING (LOSS) INCOME	2,162	2,243	6,687	6,850
Margin percentage (percent)	50.70%	52.00%	52.20%	52.70%
Consumer
Segment information
Revenues	1,503	1,536	4,508	4,640
Expenses	580	585	1,657	1,720
OPERATING (LOSS) INCOME	923	951	2,851	2,920
Margin percentage (percent)	61.40%	61.90%	63.20%	62.90%
Business
Segment information
Revenues	1,544	1,541	4,573	4,586
Expenses	958	936	2,776	2,789
OPERATING (LOSS) INCOME	586	605	1,797	1,797
Margin percentage (percent)	38.00%	39.30%	39.30%	39.20%
Wholesale
Segment information
Revenues	878	910	2,695	2,818
Expenses	293	304	868	929
OPERATING (LOSS) INCOME	585	606	1,827	1,889
Margin percentage (percent)	66.60%	66.60%	67.80%	67.00%
Data Hosting
Segment information
Revenues	342	327	1,023	960
Expenses	274	246	811	716
OPERATING (LOSS) INCOME	$ 68	$ 81	$ 212	$ 244
Margin percentage (percent)	19.90%	24.80%	20.70%	25.40%