Fair Value Measurements (Carrying Amounts and Estimated Fair Values for Certain Financial Instruments) (Detail) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016	[1]	Dec. 31, 2015	[1]
Financial assets:
Cash and due from banks		$ 2,681	$ 2,514	[1]	$ 2,392		$ 2,540
Other short-term investments	[2]	1,825	2,753
Held-to-maturity securities	[3]	18	24
Loans and leases held for sale	[4]	607	492
Commercial and industrial loans		44,340	41,170
Commercial mortgage loans		6,974	6,604
Commercial construction loans		4,657	4,553
Commercial leases		3,600	4,068
Residential mortgage loans		15,504	15,591
Home equity		6,402	7,014
Automobile loans		8,976	9,112
Credit card		2,470	2,299
Other consumer loans		2,342	1,559
Portfolio loans and leases, net		94,162	90,774
Financial liabilities:
Deposits		108,835	103,162
Federal funds purchased		1,925	174
Other short-term borrowings		573	4,012
Long-term debt	[2]	14,426	14,904
Fair Value, Inputs, Level 1
Financial assets:
Cash and due from banks		2,681	2,514
Other short-term investments		1,825	2,753
Other securities		0	0
Held-to-maturity securities		0	0
Loans and leases held for sale		0	0
Commercial and industrial loans		0	0
Commercial mortgage loans		0	0
Commercial construction loans		0	0
Commercial leases		0	0
Residential mortgage loans		0	0
Home equity		0	0
Automobile loans		0	0
Credit card		0	0
Other consumer loans		0	0
Unallocated Allowance for Loan and Lease Losses		0	0
Portfolio loans and leases, net		0	0
Financial liabilities:
Deposits		0	0
Federal funds purchased		1,925	174
Other short-term borrowings		0	0
Long-term debt		14,287	15,045
Fair Value, Inputs, Level 2
Financial assets:
Cash and due from banks		0	0
Other short-term investments		0	0
Other securities		552	612
Held-to-maturity securities		0	0
Loans and leases held for sale		0	0
Commercial and industrial loans		0	0
Commercial mortgage loans		0	0
Commercial construction loans		0	0
Commercial leases		0	0
Residential mortgage loans		0	0
Home equity		0	0
Automobile loans		0	0
Credit card		0	0
Other consumer loans		0	0
Unallocated Allowance for Loan and Lease Losses		0	0
Portfolio loans and leases, net		0	0
Financial liabilities:
Deposits		108,782	103,123
Federal funds purchased		0	0
Other short-term borrowings		573	4,012
Long-term debt		445	529
Fair Value, Inputs, Level 3
Financial assets:
Cash and due from banks		0	0
Other short-term investments		0	0
Other securities		0	0
Held-to-maturity securities		18	24
Loans and leases held for sale		63	93
Commercial and industrial loans		44,668	41,718
Commercial mortgage loans		6,851	6,490
Commercial construction loans		4,688	4,560
Commercial leases		3,180	3,705
Residential mortgage loans		15,688	15,996
Home equity		6,719	7,410
Automobile loans		8,717	8,832
Credit card		2,759	2,616
Other consumer loans		2,428	1,621
Unallocated Allowance for Loan and Lease Losses		0	0
Portfolio loans and leases, net		95,698	92,948
Financial liabilities:
Deposits		0	0
Federal funds purchased		0	0
Other short-term borrowings		0	0
Long-term debt		0	0
Net Carrying Amount
Financial assets:
Cash and due from banks		2,681	2,514
Other short-term investments		1,825	2,753
Other securities		552	612
Held-to-maturity securities		18	24
Loans and leases held for sale		63	93
Commercial and industrial loans		43,825	40,519
Commercial mortgage loans		6,894	6,539
Commercial construction loans		4,625	4,530
Commercial leases		3,582	4,054
Residential mortgage loans		15,244	15,365
Home equity		6,366	6,968
Automobile loans		8,934	9,074
Credit card		2,314	2,182
Other consumer loans		2,309	1,526
Unallocated Allowance for Loan and Lease Losses		(110)	(120)
Portfolio loans and leases, net		93,983	90,637
Financial liabilities:
Deposits		108,835	103,162
Federal funds purchased		1,925	174
Other short-term borrowings		573	4,012
Long-term debt		14,426	14,904
Total Fair Value
Financial assets:
Cash and due from banks		2,681	2,514
Other short-term investments		1,825	2,753
Other securities		552	612
Held-to-maturity securities		18	24
Loans and leases held for sale		63	93
Commercial and industrial loans		44,668	41,718
Commercial mortgage loans		6,851	6,490
Commercial construction loans		4,688	4,560
Commercial leases		3,180	3,705
Residential mortgage loans		15,688	15,996
Home equity		6,719	7,410
Automobile loans		8,717	8,832
Credit card		2,759	2,616
Other consumer loans		2,428	1,621
Unallocated Allowance for Loan and Lease Losses		0	0
Portfolio loans and leases, net		95,698	92,948
Financial liabilities:
Deposits		108,782	103,123
Federal funds purchased		1,925	174
Other short-term borrowings		573	4,012
Long-term debt		$ 14,732	$ 15,574

[1] Effective in the fourth quarter of 2018, Fifth Third retrospectively applied a change in its accounting policy for investments in affordable housing projects that qualify for LIHTC in accordance with ASU 2014-01. Refer to Note 1 for additional information.

[2] Includes $ 40 and $ 62 of other short-term investments, $ 668 and $ 1,297 of portfolio loans and leases, $ (4) and $ (6) of ALLL, $ 5 and $ 7 of other assets, $ 1 and $ 2 of other liabilities and $ 606 and $ 1,190 of long-term debt from consolidated VIEs that are included in their respec tive captions above at December 31, 2018 and 2017 , respectively. For further information, refer to Note 10 .

[3] Fair value of $ 18 and $ 24 at December 31, 2018 and 2017 , respectively .

[4] Includes $ 537 and $ 399 of residential mortgage loans held for sale measured at fair value and $7 and $0 of commercial loans held for sale measured at fair value at December 31, 2018 and 2017 , respectively.