Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016
Deferred Tax Assets (Liabilities) [Line Items]
Recognized Income Tax Benefit	$ 16	$ 0	$ 3,300
Deferred Tax Assets:
Deferred revenue	364		351		$ 364
Unutilized tax net operating loss carry forwards	4,550		4,959		4,550
Fixed assets and intangible assets	95		115		95
Other	471		501		471
Total Deferred Tax Assets	5,480		5,926		5,480
Deferred Tax Liabilities:
Deferred revenue	(57)		(58)		(57)
Fixed assets and intangible assets	(962)		(924)		(962)
Deferred Tax Liabilities, Intangible Assets	(357)		(399)		(357)
Other	(120)		(350)		(120)
Total Deferred Tax Liabilities	(1,496)		(1,731)		(1,496)
Net Deferred Tax Assets before valuation allowance	3,984		4,195		3,984
Valuation Allowance	(862)		(1,002)		(862)
Net Deferred Tax (Liability) Asset after Valuation Allowance	(3,122)		(3,193)		(3,122)
U.S. Internal Revenue Service (IRS)
Deferred Tax Assets (Liabilities) [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount				$ 100
Recognized Income Tax Benefit	(110)		3,300
Deferred Tax Liabilities:
Valuation Allowance	(900)		$ (1,000)		(900)
Operating Loss Carryforwards	$ 9,037				9,037
Geographic Distribution, Foreign [Member]
Deferred Tax Assets (Liabilities) [Line Items]
Recognized Income Tax Benefit					$ 82