Current Expected Credit Loss (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
Liabilities for Off-Balance Sheet Assets [Roll Forward]
Balance at December 31, 2019, Off-Balance Sheet Assets	$ 0
Cumulative effect of accounting change, Off-Balance Sheet Assets	12
Current period provision, Off-Balance Sheet Assets	(1)
Other, Off-Balance Sheet Assets	0
Balance at September 30, 2020, Off-Balance Sheet Assets	11
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019, Total	503
Cumulative effect of accounting change, Total	109
Current period provision, Total	(5)
Write-offs charged against the allowance, Total	(2)
Other, Total	(10)
Balance at September 30, 2020, Total	595
Trade Accounts Receivable [Member]
Financing Receivable Allowance for Credit Losses [Roll Forward]
Balance at December 31, 2019, Trade and Other	34
Cumulative effect of accounting change, Trade and Other	52
Current period provision, Trade and Other	0
Write-offs charged against the allowance, Trade and Other	(1)
Other, Trade and Other	0
Balance at September 30, 2020, Trade and Other	85
Loans and Finance Receivables [Member]
Financing Receivable Allowance for Credit Losses [Roll Forward]
Balance at December 31, 2019, Trade and Other	469
Cumulative effect of accounting change, Trade and Other	45
Current period provision, Trade and Other	(4)
Write-offs charged against the allowance, Trade and Other	(1)
Other, Trade and Other	(10)
Balance at September 30, 2020, Trade and Other	$ 499