Selected Quarterly Financial Data (Unaudited) - Additional Information (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effect of Fourth Quarter Events [Line Items]
Research and Development tax credit, amount				$ 60
Research and Development tax credit, per share impact				$ 0.03
Gain related to release of excess reserve for expansion of customer remediation programs resulting from cyber attack, net of tax							18
Gain related to release of excess reserve for expansion of customer remediation programs resulting from cyber attack, net of tax, per diluted share (in usd per share)							$ 0.01
Loss on interest rate swaps							24
Loss on interest rate swaps, per diluted share							$ 0.01
Gain on strategic investment, net of tax							32
Gain on strategic investment, net of tax, per diluted share							$ 0.01
Gain on disposition of business		11	10
Net gain on disposition of business, per share impact		$ 0.01	$ 0.01
Special tax charges related to tax-related reorganizations, amount per diluted share	$ (0.48)	$ (0.27)	$ (0.32)	$ (0.26)	$ (0.39)	$ (0.28)	$ (0.29)	$ (0.27)	$ (1.33)	$ (1.23)	$ (1.10)
Special tax charges related to tax-related reorganizations, amount									772	918	640
Tax-Related Reorganizations
Effect of Fourth Quarter Events [Line Items]
Special tax charges related to tax-related reorganizations, amount per diluted share	$ 0.00	$ 0.01			$ 0.01
Special tax charges related to tax-related reorganizations, amount	$ 4	$ 23			$ 11