Customer Financing (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Customer Financing [Line Items]
Financing Receivable, Individually Evaluated for Impairment	$ 379		$ 379		$ 391
Impaired Financing Receivable, Recorded Investment	379		379		380
Notes	415		415		420
Financing Receivable, Nonaccrual	379		379		$ 380
Impaired Financing Receivable, Interest Income, Cash Basis Method	5	$ 13	11	$ 21
Sales-Type and Direct Financing Leases, Lease Income	12	14	25	29
Operating Lease, Lease Income	19	31	37	62
Operating Lease, Variable Lease Income	3	3	5	4
Sales-type and Direct Financing Leases, Profit (Loss)	$ 20	6	$ 36	10
Financial Asset, Past Due
Customer Financing [Line Items]
Notes		$ 8		$ 8
CCC Credit Rating
Customer Financing [Line Items]
Percentage of Credit Default Rates Applied to Customers	24.20%		24.20%
B Credit Rating
Customer Financing [Line Items]
Percentage of Credit Default Rates Applied to Customers	6.50%		6.50%
BB Credit Rating
Customer Financing [Line Items]
Percentage of Credit Default Rates Applied to Customers	2.80%		2.80%
BBB Credit Rating
Customer Financing [Line Items]
Percentage of Credit Default Rates Applied to Customers	0.20%		0.20%