Annual report pursuant to Section 13 and 15(d)

Accounts Receivable Accounts Receivable (Accounts Receivable) (Details)

v3.10.0.1
Accounts Receivable Accounts Receivable (Accounts Receivable) (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2018
USD ($)
installment
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Accounts Receivable, Net, Current [Abstract]      
Accounts receivable, gross $ 1,899 $ 1,771  
Less allowance for doubtful accounts (112) (91)  
Accounts receivable, net 1,787 1,680  
Installment sales plan      
Accounts Receivable, Net, Current [Abstract]      
Accounts receivable, gross 1,533 1,396  
Credit Card Receivable [Member]      
Accounts Receivable, Net, Current [Abstract]      
Accounts receivable, gross 269 295  
Other receivables [Member]      
Accounts Receivable, Net, Current [Abstract]      
Accounts receivable, gross 97 80  
SG&A      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Finance income from company branded credit card issued by financial institution $ 118 $ 105 $ 100
Minimum | Installment sales plan      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Number of installments plan permits for customers | installment 2    
Maximum | Installment sales plan      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Number of installments plan permits for customers | installment 5