Customer Financing (Financing Receivable Credit Quality Indicators) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 100
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	85
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	16
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	297
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	177
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	688
Carrying value of financing receivables	1,363	$ 1,472
CCC Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	35
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	244
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	177
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	13
Carrying value of financing receivables	469
B Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	53
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	174
Carrying value of financing receivables	227
BB Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	100
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	50
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	16
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	148
Carrying value of financing receivables	314
BBB Credit Rating
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	353
Carrying value of financing receivables	$ 353