Derivatives and Hedging Activities (Details Textuals) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Derivative [Line Items]
Derivative asset not offset	$ 0		$ 0		$ 0
Derivative liabilities not offset	0		0		0
Margin on interest rate swaps	41,000,000		41,000,000		55,000,000
Cumulative amount of fair value hedging adjustment	6,000,000		6,000,000		184,000,000
Net increase (reduction) in interest expense on long term debt and other	21,000,000	$ 23,000,000	81,000,000	$ 46,000,000
Other Expense [Member]
Derivative [Line Items]
Gain (loss) in changes in fair value of derivatives not designated as hedges	20,000,000	10,000,000	69,000,000	40,000,000
Fair Value Hedging [Member]
Derivative [Line Items]
Notional amount of long-term debt	8,800,000,000		8,800,000,000		13,800,000,000
Net Investment Hedges [Member]
Derivative [Line Items]
Notional amounts of derivatives	3,000,000,000.0		3,000,000,000.0		2,900,000,000
Reported Value Measurement [Member]
Derivative [Line Items]
Notional amount of long-term debt	8,700,000,000		8,700,000,000		$ 13,500,000,000
Accumulated Other Comprehensive Loss [Member]
Derivative [Line Items]
Gain (loss) on net investment hedges, net of taxes	$ 50,000,000	$ (3,000,000)	$ 29,000,000	$ 59,000,000