Derivatives and Hedging Activities (Details Textuals) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Margin on interest rate swap not netted	$ 47,000,000	$ 84,000,000
Net increases (reductions) in interest expense on long term debt and other	102,000,000	51,000,000	$ (133,000,000)
Net losses related to hedges of investments in foreign operations	(140,000,000)
Other Expense [Member]
Derivatives, Fair Value [Line Items]
Gain (loss) in changes of fair value of derivatives not designated as hedges	64,000,000	60,000,000	(29,000,000)
Gain on embedded derivatives	3,000,000		0
Loss on embedded derivatives		11,000,000
Fair Value Hedges [Member]
Derivatives, Fair Value [Line Items]
Fixed-rate debt obligations desginated in fair value relationships	22,600,000,000	24,000,000,000.0
Cumulative amount of fair value hedging adjustments	217,000,000	(241,000,000)
Net Investment Hedges [Member]
Derivatives, Fair Value [Line Items]
Notional amounts of foreign currency derivatives	9,800,000,000	9,600,000,000
Net losses related to hedges of investments in foreign operations	140,000,000	328,000,000	$ 370,000,000
Credit Valuation Adjustment [Member]
Derivatives, Fair Value [Line Items]
Fixed-rate debt obligations desginated in fair value relationships	0	0
Reported Value Measurement [Member]
Derivatives, Fair Value [Line Items]
Fixed-rate debt obligations desginated in fair value relationships	$ 22,700,000,000	$ 23,700,000,000