Derivatives and Hedging Activities (Details Textuals) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 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	76,000,000		76,000,000		84,000,000
Cumulative amount of fair value hedging adjustment	199,000,000		199,000,000		(241,000,000)
Net increase (reduction) in interest expense on long term debt and other	36,000,000	$ 13,000,000	74,000,000	$ (1,000,000)
Other Expense [Member]
Derivative [Line Items]
Gain (loss) in changes in fair value of derivatives not designated as hedges	23,000,000	55,000,000	27,000,000	34,000,000
Changes in fair value of an embedded derivative		4,000,000		6,000,000
Fair Value Hedging [Member]
Derivative [Line Items]
Notional amount of long-term debt	22,100,000,000		22,100,000,000		24,000,000,000.0
Net Investment Hedges [Member]
Derivative [Line Items]
Notional amounts of derivatives	9,700,000,000		9,700,000,000		9,600,000,000
Reported Value Measurement [Member]
Derivative [Line Items]
Notional amount of long-term debt	22,200,000,000		22,200,000,000		$ 23,700,000,000
AOCI Attributable to Parent [Member]
Derivative [Line Items]
Gain (loss) on net investment hedges, net of taxes	$ 87,000,000	$ 320,000,000	$ (75,000,000)	$ 158,000,000