Derivatives and Hedging Activities (Details Textuals) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Derivative [Line Items]
Margin on interest rate swaps	$ 23,000,000		$ 23,000,000		$ 34,000,000
Carrying values of hedged liabilities	13,200,000,000		13,200,000,000		16,400,000,000
Cumulative amount of fair value hedging adjustment	424,000,000		424,000,000		622,000,000
Net decrease in interest expense on long term debt and other	63,000,000	$ 81,000,000	136,000,000	$ (102,000,000)
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative notional amount	14,400,000,000		14,400,000,000		14,400,000,000
Other Expense
Derivative [Line Items]
(Gain) loss on changes in fair value of derivatives and related underlying foreign currency exposures	9,000,000	2,000,000	14,000,000	(18,000,000)
Fair Value Hedging | Fixed-Rate Debt Obligations
Derivative [Line Items]
Fixed-rate debt obligations designated in fair value hedging relationships	12,900,000,000		12,900,000,000		15,800,000,000
Net Investment Hedges
Derivative [Line Items]
Notional amounts of derivatives	10,800,000,000		10,800,000,000		$ 10,500,000,000
Net hedges of investments in foreign operations	108,000,000	339,000,000	102,000,000	(393,000,000)
Reclassifications out of AOCI	$ 0	$ 0	$ 0	$ 0