Fair Value Disclosures (Schedule of Assets and Liabilities Measured at Fair Value) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Trading securities	$ 463	$ 381
AFS securities	20,936	22,104
LHFS	1,692	1,222
Residential MSRs	954	1,047	892	627
Private equity and similar investments	322	291
Assets measured at fair value	25,261	25,909
Short-term borrowings	170	84
Total liabilities	1,009	1,054
Level 1 [Member]
Trading securities	280	256
LHFS	0	0
Residential MSRs	0	0
Private equity and similar investments	0	0
Assets measured at fair value	288	266
Short-term borrowings	0	0
Total liabilities	0	0
Level 2 [Member]
Trading securities	170	125
LHFS	1,692	1,222
Residential MSRs	0	0
Private equity and similar investments	0	0
Assets measured at fair value	22,849	23,441
Short-term borrowings	170	84
Total liabilities	1,008	1,040
Level 3 [Member]
Trading securities	13	0
LHFS	0	0
Residential MSRs	954	1,047
Private equity and similar investments	322	291
Assets measured at fair value	2,124	2,202
Short-term borrowings	0	0
Total liabilities	1	14
U.S. Treasury Securities
AFS securities	1,095	595
U.S. Treasury Securities | Level 2 [Member]
AFS securities	1,095	595
MBS Issued by GSE
AFS securities	16,234	17,929
MBS Issued by GSE | Level 2 [Member]
AFS securities	16,234	17,929
States and Political Subdivisions [Member]
AFS securities	1,954	1,851
States and Political Subdivisions [Member] | Level 2 [Member]
AFS securities	1,954	1,851
Non-Agency MBS [Member]
AFS securities	277	291
Non-Agency MBS [Member] | Level 2 [Member]
AFS securities	277	291
Other Securities [Member]
AFS securities	43	45
Other Securities [Member] | Level 1 [Member]
AFS securities	8	10
Other Securities [Member] | Level 2 [Member]
AFS securities	35	35
Covered Securities [Member]
AFS securities	1,333	1,393
Covered Securities [Member] | Level 2 [Member]
AFS securities	523	532
Covered Securities [Member] | Level 3 [Member]
AFS securities	810	861
Interest Rate Contract [Member]
Derivative assets	892	862
Derivative liabilities	835	967
Interest Rate Contract [Member] | Level 2 [Member]
Derivative assets	867	859
Derivative liabilities	834	953
Interest Rate Contract [Member] | Level 3 [Member]
Derivative assets	25	3
Derivative liabilities	1	14
Foreign Exchange Contracts [Member]
Derivative assets	2	2
Derivative liabilities	4	3
Foreign Exchange Contracts [Member] | Level 2 [Member]
Derivative assets	2	2
Derivative liabilities	$ 4	$ 3