Summary of Significant Accounting Policies Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Restricted Cash, Current		$ 182	$ 0
Other Non-current Assets		365	139
Accounts Receivable, after Allowance for Credit Loss, Current		1,089		$ 1,051
Accounts Receivable, Net of Allowance for Uncollectible Accounts of $0 at December 31, 2019 and $123 at December 31, 2018		$ 1,241	1,130
VENEZUELA | Revenue Recognition [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative Effect of Change in Accounting Estimate	$ 230
Other Non-current Assets			158
Accounts Receivable, Net of Allowance for Uncollectible Accounts of $0 at December 31, 2019 and $123 at December 31, 2018			$ 72
Minimum
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Product warranty period		1 year
Maximum
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Product warranty period		5 years