Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Millions		Dec. 31, 2017		Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	[1]	$ 5,093		$ 6,067
Available-for-sale Securities	[2]	31,416		30,672
Loans Held-for-sale, Fair Value Disclosure		1,577		3,540
Loans Receivable, Fair Value Disclosure		196		222
Long-term Debt, Fair Value		530		963
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	[3]	608		881
Available-for-sale Securities	[3]	4,382		5,507
Loans Held-for-sale, Fair Value Disclosure	[4]	0		0
Trading Liabilities, Fair Value Disclosure	[3]	769		846
Long-term Debt, Fair Value	[5]	0		0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	[3]	4,469		5,158
Available-for-sale Securities	[3]	26,544		24,532
Loans Held-for-sale, Fair Value Disclosure	[4]	2,239		4,161
Trading Liabilities, Fair Value Disclosure	[3]	498		483
Long-term Debt, Fair Value	[5]	8,834		11,051
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	[3]	16		28
Available-for-sale Securities	[3]	490		633
Loans Held-for-sale, Fair Value Disclosure	[4]	54		17
Trading Liabilities, Fair Value Disclosure	[3]	16		22
Long-term Debt, Fair Value	[5]	1,058		728
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		5,093		6,067
Available-for-sale Securities		31,416		30,672
Loans Held-for-sale, Fair Value Disclosure		1,577		3,540
Loans Receivable, Fair Value Disclosure		196		222
Servicing Asset at Fair Value, Amount		1,710		1,572
Trading Liabilities, Fair Value Disclosure		1,283		1,351
Long-term Debt, Fair Value		530		963
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		608		881
Available-for-sale Securities		4,382		5,507
Loans Held-for-sale, Fair Value Disclosure		0		0
Loans Receivable, Fair Value Disclosure		0		0
Servicing Asset at Fair Value, Amount		0		0
Trading Liabilities, Fair Value Disclosure		769		846
Deposits, Fair Value Disclosure		0		0
Long-term Debt, Fair Value		0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		7,571		8,688
Available-for-sale Securities		26,544		24,532
Loans Held-for-sale, Fair Value Disclosure		1,577		3,528
Loans Receivable, Fair Value Disclosure		0		0
Servicing Asset at Fair Value, Amount		0		0
Trading Liabilities, Fair Value Disclosure		4,532		4,987
Deposits, Fair Value Disclosure		236		78
Long-term Debt, Fair Value		530		963
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		16		28
Available-for-sale Securities		490		633
Loans Held-for-sale, Fair Value Disclosure		0		12
Loans Receivable, Fair Value Disclosure		196		222
Servicing Asset at Fair Value, Amount		1,710		1,572
Trading Liabilities, Fair Value Disclosure		16		22
Deposits, Fair Value Disclosure		0		0
Long-term Debt, Fair Value		0		0
US Treasury Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		157		539
Available-for-sale Securities		4,331		5,405
Trading Liabilities, Fair Value Disclosure		577		697
US Treasury Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Available-for-sale Securities		0		0
Trading Liabilities, Fair Value Disclosure		0		0
US Treasury Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Available-for-sale Securities		0		0
Trading Liabilities, Fair Value Disclosure		0		0
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Available-for-sale Securities		0		0
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		395		480
Available-for-sale Securities		259		313
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Available-for-sale Securities		0		0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Available-for-sale Securities		0		0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		61		134
Available-for-sale Securities		617		275
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Available-for-sale Securities		0		4
Collateralized Loan Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities				0
Collateralized Loan Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities				1
Collateralized Loan Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities				0
Other Debt Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Available-for-sale Securities		0		0
Trading Liabilities, Fair Value Disclosure		0		0
Other Debt Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		655		656
Available-for-sale Securities		12		30
Trading Liabilities, Fair Value Disclosure		289		255
Other Debt Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Available-for-sale Securities		5		5
Trading Liabilities, Fair Value Disclosure		0		0
Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		118		140
Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		56		49
Available-for-sale Securities		51	[6]	102	[7]
Trading Liabilities, Fair Value Disclosure		9
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Available-for-sale Securities		0	[6]	0	[7]
Trading Liabilities, Fair Value Disclosure		0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Available-for-sale Securities		418	[6]	540	[7]
Trading Liabilities, Fair Value Disclosure		0
Derivative Financial Instruments, Assets [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		802		984
Derivative Financial Instruments, Assets [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		395		293
Derivative Financial Instruments, Assets [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		3,493		4,193
Derivative Financial Instruments, Assets [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		16		28
Trading Loans [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Trading Loans [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		2,149		2,517
Trading Loans [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		0		0
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		0		0
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		8		10
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Liabilities, Fair Value Disclosure		408		398
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Liabilities, Fair Value Disclosure		183		149
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Liabilities, Fair Value Disclosure		4,243		4,731
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Liabilities, Fair Value Disclosure		16		22
Brokered Time Deposits [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits, Fair Value Disclosure		236		78
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	[3]	5,093		6,067
Available-for-sale Securities	[3]	31,416		30,672
Loans Held-for-sale, Fair Value Disclosure	[4]	2,293		4,178
Trading Liabilities, Fair Value Disclosure	[3]	1,283		1,351
Long-term Debt, Fair Value	[5]	9,892		11,779
Estimate of Fair Value Measurement [Member] | US Treasury Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		157		539
Available-for-sale Securities		4,331		5,405
Trading Liabilities, Fair Value Disclosure		577		697
Estimate of Fair Value Measurement [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		395		480
Available-for-sale Securities		259		313
Estimate of Fair Value Measurement [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		61		134
Available-for-sale Securities		617		279
Estimate of Fair Value Measurement [Member] | Collateralized Loan Obligations [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities				1
Estimate of Fair Value Measurement [Member] | Other Debt Obligations [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		655		656
Available-for-sale Securities		17		35
Trading Liabilities, Fair Value Disclosure		289		255
Estimate of Fair Value Measurement [Member] | Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		118		140
Estimate of Fair Value Measurement [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		56		49
Available-for-sale Securities		469	[6]	642	[7]
Trading Liabilities, Fair Value Disclosure		9
Estimate of Fair Value Measurement [Member] | Trading Loans [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		2,149		2,517
Estimate of Fair Value Measurement [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		8		10
Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	[3]	5,093		6,067
Available-for-sale Securities	[3]	31,416		30,672
Loans Held-for-sale, Fair Value Disclosure	[4]	2,290		4,169
Trading Liabilities, Fair Value Disclosure	[3]	1,283		1,351
Long-term Debt, Fair Value	[5]	9,785		11,748
Netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		(3,102)	[8]	(3,530)	[9]
Trading Liabilities, Fair Value Disclosure		(4,034)	[8]	(4,504)	[9]
Netting [Member] | Derivative Financial Instruments, Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		(3,102)	[8]	(3,530)	[9]
Netting [Member] | Derivative Financial Instruments, Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Liabilities, Fair Value Disclosure		(4,034)	[8]	(4,504)	[9]
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		700		567
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Trading Liabilities, Fair Value Disclosure				0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		700		567
Trading Liabilities, Fair Value Disclosure				1
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		0		0
Trading Liabilities, Fair Value Disclosure				0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		22,704		22,436
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		0		0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		22,704		22,436
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		0		0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		2,086		1,226
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		0		0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		2,086		1,226
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		0		0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		700		567
Trading Liabilities, Fair Value Disclosure				1
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Estimate of Fair Value Measurement [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		22,704		22,436
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Estimate of Fair Value Measurement [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		2,086		1,226
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		59		74
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		0		0
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		0		0
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		59		74
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		866		252
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		0		0
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		866		252
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		0		0
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Estimate of Fair Value Measurement [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		59		74
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Estimate of Fair Value Measurement [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities		$ 866		$ 252

[1] Includes trading securities pledged as collateral where counterparties have the right to sell or repledge the collateral of $1,086 million and $1,437 million at December 31, 2017 and December 31, 2016, respectively.

[2] Includes securities AFS pledged as collateral where counterparties have the right to sell or repledge the collateral of $223 million and $0 million at December 31, 2017 and December 31, 2016, respectively.

[3] Trading assets and derivative instruments, securities AFS, and trading liabilities and derivative instruments that are classified as level 1 are valued based on quoted prices observed in active markets. For those instruments classified as level 2 or 3, refer to the respective valuation discussions within this footnote.

[4] LHFS are generally valued based on observable current market prices or, if quoted market prices are not available, quoted market prices of similar instruments. Refer to the LHFS section within this footnote for further discussion. When valuation assumptions are not readily observable in the market, instruments are valued based on the best available data to approximate fair value. This data may be internally developed and considers risk premiums that a market participant would require under then-current market conditions.

[5] Fair values for short-term borrowings and certain long-term debt are based on quoted market prices for similar instruments or estimated discounted cash flows utilizing the Company’s current incremental borrowing rate for similar types of instruments. Refer to the respective valuation section within this footnote for valuation information related to long-term debt that the Company measures at fair value. For level 3 debt, the terms are unique in nature or there are no similar instruments that can be used to value the instrument without using significant unobservable assumptions.

[6] Includes $49 million of mutual fund investments, $15 million of FHLB of Atlanta stock, $403 million of Federal Reserve Bank of Atlanta stock, and $2 million of other.

[7] Includes $102 million of mutual fund investments, $132 million of FHLB of Atlanta stock, $402 million of Federal Reserve Bank of Atlanta stock, and $6 million of other.

[8] Amounts represent offsetting cash collateral received from, and paid to, the same derivative counterparties, and the impact of netting derivative assets and derivative liabilities when a legally enforceable master netting agreement or similar agreement exists. See Note 17, "Derivative Financial Instruments," for additional information.

[9] Amounts represent offsetting cash collateral received from, and paid to, the same derivative counterparties, and the impact of netting derivative assets and derivative liabilities when a legally enforceable master netting agreement or similar agreement exists. See Note 17, "Derivative Financial Instruments," for additional information.