Restructuring - Recognized Restructuring Costs by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	$ 4	$ 0	$ 112	$ 0
Marketplaces
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	3	0	63	0
Payments
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	1	0	49	0
Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	4	0	112	0
Employee Severance and Benefits | Marketplaces
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	3	0	63	0
Employee Severance and Benefits | Payments
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	1	0	49	0
Other Associated Costs
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	0	0	0	0
Other Associated Costs | Marketplaces
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	0	0	0	0
Other Associated Costs | Payments
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	$ 0	$ 0	$ 0	$ 0