Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Restricted cash	$ 63	$ 63
Equity securities minimum restriction period	1 year
Summary Of Significant Accounting Policies [Line Items]
Percent of historical transactions	80.00%
Selling price, marginal percentage rate	15.00%
Minimum contractual term for trade receivables	1 year
Net cash provided by (used for) operating activities from continuing operations	$ 1,165	1,021	$ (637)
Net cash used for financing activities from continuing operations	1,042	2,398	1,763
Accounting Standards Update 2015-03 | Long-term Debt
Summary Of Significant Accounting Policies [Line Items]
Debt issuance costs, net	25	41
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2016-09
Summary Of Significant Accounting Policies [Line Items]
Excess tax benefit	5
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2016-09, Statutory Tax Withholding Component
Summary Of Significant Accounting Policies [Line Items]
Net cash provided by (used for) operating activities from continuing operations	17	16	48
Net cash used for financing activities from continuing operations	17	$ 16	$ 48
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2016-09, Excess Tax Benefit Component
Summary Of Significant Accounting Policies [Line Items]
Net cash provided by (used for) operating activities from continuing operations	6
Net cash used for financing activities from continuing operations	$ 5
Minimum
Summary Of Significant Accounting Policies [Line Items]
Intangible assets estimated useful lives	1 year
Maximum
Summary Of Significant Accounting Policies [Line Items]
Intangible assets estimated useful lives	10 years
Building and Building Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life, years	5 years
Building and Building Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life, years	40 years
Machinery And Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life, years	2 years
Machinery And Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life, years	10 years