Merger Restructuring and Planned Headquarters Closure (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Jan. 07, 2015 mo
RESTRUCTURING AND PLANNED HEADQUARTERS CLOSURE [Abstract]
Employee severance and relocation, exit of corporate headquarters; leasehold improvements and office equipment expense low end		$ 25
Employee severance and relocation, exit of corporate headquarters; leasehold improvements and office equipment expense high end		40
Estimated cost of leasehold improvements and office equipment low end	$ 10
Estimated cost of leasehold improvements and office equipment high end		12
Relocation incentives		$ 3
Estimated remaining life | mo			12
Estimated remaining life high end | mo			18