Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($)		Jun. 30, 2018		Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	[1]	$ 11,995,000,000		$ 9,785,000,000
Trading Securities	[2]	5,050,000,000		5,093,000,000
Available-for-sale Securities	[3],[4]	30,942,000,000		30,947,000,000	[5]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group	[6]	2,283,000,000		2,290,000,000
Loans Held-for-sale, Fair Value Disclosure		2,005,000,000		1,577,000,000
Loans and Leases Receivable, Excluding Fair Value Loans		144,758,000,000		142,985,000,000
Loans Receivable, Fair Value Disclosure		177,000,000		196,000,000
Other Assets	[3]	8,792,000,000		9,418,000,000
Other Assets, Fair Value Disclosure				56,000,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt		0		0
Long-term Debt, Fair Value		0		0
Trading Securities		509,000,000		608,000,000
Available-for-sale Securities		4,126,000,000		4,331,000,000
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		0		0
Loans Held-for-sale, Fair Value Disclosure		0		0
Loans and Leases Receivable, Excluding Fair Value Loans		0		0
Loans Receivable, Fair Value Disclosure		0		0
Other Assets		0		0
Trading Liabilities, Fair Value Disclosure		910,000,000		769,000,000
Other Assets, Fair Value Disclosure		126,000,000		56,000,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt		10,227,000,000		8,304,000,000
Long-term Debt, Fair Value		220,000,000		530,000,000
Trading Securities		4,522,000,000		4,469,000,000
Available-for-sale Securities		26,816,000,000		26,544,000,000
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		231,000,000		662,000,000
Loans Held-for-sale, Fair Value Disclosure		2,005,000,000		1,577,000,000
Loans and Leases Receivable, Excluding Fair Value Loans		0		0
Loans Receivable, Fair Value Disclosure		0		0
Other Assets		0		0
Trading Liabilities, Fair Value Disclosure		1,032,000,000		498,000,000
Other Assets, Fair Value Disclosure		0		0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt		1,602,000,000		1,058,000,000
Long-term Debt, Fair Value		0		0
Trading Securities		19,000,000		16,000,000
Available-for-sale Securities		0		72,000,000
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		49,000,000		54,000,000
Loans Held-for-sale, Fair Value Disclosure		0		0
Loans and Leases Receivable, Excluding Fair Value Loans		142,267,000,000		141,379,000,000
Loans Receivable, Fair Value Disclosure		177,000,000		196,000,000
Other Assets		493,000,000		418,000,000
Trading Liabilities, Fair Value Disclosure		16,000,000		16,000,000
Other Assets, Fair Value Disclosure		0		0
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		220,000,000		530,000,000
Trading Securities		5,050,000,000		5,093,000,000
Available-for-sale Securities		30,942,000,000	[7]	30,947,000,000	[8]
Loans Held-for-sale, Fair Value Disclosure		2,005,000,000		1,577,000,000
Loans Receivable, Fair Value Disclosure		177,000,000		196,000,000
Servicing Asset at Fair Value, Amount		1,959,000,000		1,710,000,000
Trading Liabilities, Fair Value Disclosure		1,958,000,000		1,283,000,000
Other Assets, Fair Value Disclosure		126,000,000	[7]	56,000,000	[8]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		0		0
Trading Securities		509,000,000		608,000,000
Available-for-sale Securities		4,126,000,000	[7]	4,331,000,000	[8]
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		910,000,000		769,000,000
Deposits, Fair Value Disclosure		0		0
Other Assets, Fair Value Disclosure		126,000,000	[7]	56,000,000	[8]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		220,000,000		530,000,000
Trading Securities		7,025,000,000		7,571,000,000
Available-for-sale Securities		26,816,000,000	[7]	26,544,000,000	[8]
Loans Held-for-sale, Fair Value Disclosure		2,005,000,000		1,577,000,000
Loans Receivable, Fair Value Disclosure		0		0
Servicing Asset at Fair Value, Amount		0		0
Trading Liabilities, Fair Value Disclosure		3,901,000,000		4,532,000,000
Deposits, Fair Value Disclosure		350,000,000		236,000,000
Other Assets, Fair Value Disclosure		0	[7]	0	[8]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		0		0
Trading Securities		19,000,000		16,000,000
Available-for-sale Securities		0	[7]	72,000,000	[8]
Loans Held-for-sale, Fair Value Disclosure		0		0
Loans Receivable, Fair Value Disclosure		177,000,000		196,000,000
Servicing Asset at Fair Value, Amount		1,959,000,000		1,710,000,000
Trading Liabilities, Fair Value Disclosure		16,000,000		16,000,000
Deposits, Fair Value Disclosure		0		0
Other Assets, Fair Value Disclosure		0	[7]	0	[8]
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		203,000,000		157,000,000
Available-for-sale Securities		4,126,000,000		4,331,000,000
Trading Liabilities, Fair Value Disclosure		779,000,000		577,000,000
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
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 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 Liabilities, Fair Value Disclosure		1,000,000
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 Liabilities, Fair Value Disclosure		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		502,000,000		395,000,000
Available-for-sale Securities		243,000,000		259,000,000
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		27,000,000		61,000,000
Available-for-sale Securities		615,000,000		617,000,000
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		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		872,000,000		655,000,000
Available-for-sale Securities		15,000,000		12,000,000
Trading Liabilities, Fair Value Disclosure		534,000,000		289,000,000
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		0		5,000,000
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		114,000,000		118,000,000
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		57,000,000		56,000,000
Trading Liabilities, Fair Value Disclosure		14,000,000		9,000,000
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
Trading Liabilities, Fair Value Disclosure		0		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
Trading Liabilities, Fair Value Disclosure		0		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		567,000,000		802,000,000
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		249,000,000		395,000,000
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		2,802,000,000		3,493,000,000
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		19,000,000		16,000,000
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		1,949,000,000		2,149,000,000
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
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
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				8,000,000
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		630,000,000		408,000,000
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		117,000,000		183,000,000
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		3,366,000,000		4,243,000,000
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		16,000,000		16,000,000
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		350,000,000		236,000,000
Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt		11,775,000,000		9,255,000,000
Long-term Debt, Fair Value		220,000,000		530,000,000
Trading Securities		5,050,000,000		5,093,000,000
Available-for-sale Securities		30,942,000,000		30,947,000,000
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		278,000,000		713,000,000
Loans Held-for-sale, Fair Value Disclosure		2,005,000,000		1,577,000,000
Loans and Leases Receivable, Excluding Fair Value Loans		143,108,000,000		141,250,000,000
Loans Receivable, Fair Value Disclosure		177,000,000		196,000,000
Other Assets		493,000,000	[9]	418,000,000	[10]
Trading Liabilities, Fair Value Disclosure		1,958,000,000		1,283,000,000
Other Assets, Fair Value Disclosure		126,000,000	[9]	56,000,000	[10]
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt		11,829,000,000		9,362,000,000
Long-term Debt, Fair Value		220,000,000		530,000,000
Trading Securities		5,050,000,000		5,093,000,000
Available-for-sale Securities		30,942,000,000		30,947,000,000
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		280,000,000		716,000,000
Loans Held-for-sale, Fair Value Disclosure		2,005,000,000		1,577,000,000
Loans and Leases Receivable, Excluding Fair Value Loans		142,267,000,000		141,379,000,000
Loans Receivable, Fair Value Disclosure		177,000,000		196,000,000
Other Assets		493,000,000	[9]	418,000,000	[10]
Trading Liabilities, Fair Value Disclosure		1,958,000,000		1,283,000,000
Other Assets, Fair Value Disclosure		126,000,000	[9]	56,000,000	[10]
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		203,000,000		157,000,000
Available-for-sale Securities		4,126,000,000		4,331,000,000
Trading Liabilities, Fair Value Disclosure		779,000,000		577,000,000
Estimate of Fair Value Measurement [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Liabilities, Fair Value Disclosure		1,000,000
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		502,000,000		395,000,000
Available-for-sale Securities		243,000,000		259,000,000
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		27,000,000		61,000,000
Available-for-sale Securities		615,000,000		617,000,000
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		872,000,000		655,000,000
Available-for-sale Securities		15,000,000		17,000,000
Trading Liabilities, Fair Value Disclosure		534,000,000		289,000,000
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		114,000,000		118,000,000
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		57,000,000		56,000,000
Trading Liabilities, Fair Value Disclosure		14,000,000		9,000,000
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		1,949,000,000		2,149,000,000
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				8,000,000
Netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		(2,503,000,000)	[11]	(3,102,000,000)	[12]
Trading Liabilities, Fair Value Disclosure		(2,869,000,000)	[11]	(4,034,000,000)	[12]
Netting [Member] | Derivative Financial Instruments, Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities		(2,503,000,000)	[11]	(3,102,000,000)	[12]
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		(2,869,000,000)	[11]	(4,034,000,000)	[12]
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		759,000,000		700,000,000
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
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		759,000,000		700,000,000
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
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		22,459,000,000		22,704,000,000
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		22,459,000,000		22,704,000,000
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		2,568,000,000		2,086,000,000
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		2,568,000,000		2,086,000,000
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		759,000,000		700,000,000
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		22,459,000,000		22,704,000,000
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		2,568,000,000		2,086,000,000
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				59,000,000
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
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
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				59,000,000
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		916,000,000		866,000,000
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		916,000,000		866,000,000
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				59,000,000
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		$ 916,000,000		$ 866,000,000

[1] Includes debt of consolidated VIEs of $174 million and $189 million at June 30, 2018 and December 31, 2017, respectively.

[2] Includes trading securities pledged as collateral where counterparties have the right to sell or repledge the collateral of $1,160 million and $1,086 million at June 30, 2018 and December 31, 2017, respectively.

[3] Beginning January 1, 2018, the Company reclassified equity securities previously presented in Securities available for sale to Other assets. Reclassifications have been made to previously reported amounts for comparability.

[4] Includes securities AFS pledged as collateral where counterparties have the right to sell or repledge the collateral of $184 million and $223 million at June 30, 2018 and December 31, 2017, respectively.

[5] Beginning January 1, 2018, the Company reclassified equity securities previously presented in Securities available for sale to Other assets on the Consolidated Balance Sheets. Reclassifications have been made to previously reported amounts for comparability. See Note 9, "Other Assets," for additional information.

[6] Includes $2.0 billion and $1.6 billion of LHFS measured at fair value at June 30, 2018 and December 31, 2017, respectively.

[7] Beginning January 1, 2018, the Company reclassified equity securities previously presented in Securities available for sale to Other assets on the Consolidated Balance Sheets. Reclassifications have been made to previously reported amounts for comparability. See Note 9, "Other Assets," for additional information.

[8] Beginning January 1, 2018, the Company reclassified equity securities previously presented in Securities available for sale to Other assets on the Consolidated Balance Sheets. Reclassifications have been made to previously reported amounts for comparability. See Note 9, "Other Assets," for additional information.

[9] Other financial assets recorded at amortized cost consist of FHLB of Atlanta stock and Federal Reserve Bank of Atlanta stock. Other financial assets recorded at fair value consist of mutual fund investments and other equity securities with readily determinable fair values.

[10] Other financial assets recorded at amortized cost consist of FHLB of Atlanta stock and Federal Reserve Bank of Atlanta stock. Other financial assets recorded at fair value consist of mutual fund investments and other equity securities with readily determinable fair values.

[11] 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 15, "Derivative Financial Instruments," for additional information.

[12] 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 15, "Derivative Financial Instruments," for additional information.