Income Taxes Income Taxes (Schedule of Net Deferred Tax Asset/Liability) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets, Gross [Abstract]
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits	$ 228	$ 260
Operating Loss Carryforwards	1,065	563
Deferred Tax Assets, Capital Loss Carryforwards	4	17
Deferred Tax Assets, Foreign Tax Credits	4,430	4,335
Deferred Tax Assets, Other Tax Carryforwards	35	35
Deferred Tax Assets, Investment in Subsidiaries	91	17
Deferred Tax Assets, Other	88	73
Valuation Allowance [Abstract]
Deferred Tax Assets Valuation Allowance Federal	(4,166)	(2,820)
Deferred Tax Assets Valuation Allowance State	(53)	(56)
Deferred Tax Assets Valuation Allowance Foreign	(84)	(162)
Deferred Tax Assets, Net of Valuation Allowance	1,638	2,262
Deferred Tax Liabilities, Gross [Abstract]
Deferred Tax Liabilities, Property, Plant and Equipment	3,672	3,376
Deferred Tax Liabilities, Other	68	105
Deferred Tax Liabilities, Gross	3,740	3,481
Deferred Tax Liabilities, Net	$ 2,102	$ 1,219