Derivatives and Hedging Activities (Schedule of Fair Value and Outstanding Notional Amounts of Derivative Instruments and Related Collateral Balances) (Details) € in Millions, ₨ in Millions, £ in Millions, $ in Millions, $ in Millions		Mar. 31, 2020 USD ($) transactions		Mar. 31, 2020 SGD ($) transactions	Mar. 31, 2020 EUR (€) transactions	Mar. 31, 2020 GBP (£) transactions	Mar. 31, 2020 INR (₨) transactions	Dec. 31, 2019 USD ($) transactions		Dec. 31, 2019 SGD ($) transactions	Dec. 31, 2019 EUR (€) transactions	Dec. 31, 2019 GBP (£) transactions	Dec. 31, 2019 INR (₨) transactions
Derivatives, Fair Value [Line Items]
Derivative assets	[1]	$ 1						$ 0
Collateral held, derivative assets	[2]	0						0
Total net derivative assets		1						0
Derivative liabilities	[1]	10						7
Collateral posted, derivative liabilities	[2]	(10)						(7)
Total net derivative liabilities		0						0
Designated as Hedges [Member] | Cash Flow Hedging [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 900						900
Derivative, number of outstanding derivative contracts (in transactions) | transactions		3		3	3	3	3
Derivative assets		$ 0						0
Derivative liabilities		9						2
Designated as Hedges [Member] | Fair Value Hedging [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 14,275						14,275
Derivative, number of outstanding derivative contracts (in transactions) | transactions		18		18	18	18	18
Derivative assets		$ 1						0
Derivative liabilities		1						4
Not Designated as Hedges [Member] | Foreign Exchange Forward [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 23	[3]	$ 1	€ 6	£ 6	₨ 596	38	[3]	$ 1	€ 9	£ 14	₨ 596
Derivative, number of outstanding derivative contracts (in transactions) | transactions		6		6	6	6	6
Derivative assets		$ 0						0
Derivative liabilities		0						1
Not Designated as Hedges [Member] | When-Issued Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 28						$ 42
Derivative, number of outstanding derivative contracts (in transactions) | transactions		2		2	2	2	2	2		2	2	2	2

[1] In addition to the derivatives disclosed in the table, the Company enters into forward contracts to purchase when-issued mortgage-backed securities as part of its community reinvestment initiatives. At March 31, 2020, the Company had two outstanding contracts with a total notional amount of $28 million and immaterial fair value. At December 31, 2019, the Company had two outstanding contracts with a total notional amount of $42 million and immaterial fair value.

[2] Collateral amounts, which consist of both cash and investment securities, are limited to the related derivative asset/liability balance and do not include excess collateral received/pledged.

[3] The foreign exchange forward contracts have notional amounts of EUR 6 million, GBP 6 million, SGD 1 million and INR 596 million as of March 31, 2020 and notional amounts of EUR 9 million, GBP 14 million, SGD 1 million and INR 596 million as of December 31, 2019.