Accumulated Other Comprehensive Loss (Tables)
 3 Months Ended
Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]  
Schedule Of Accumulated Other Comprehensive Loss
The following table presents a reconciliation of the changes in the components of accumulated other comprehensive loss and details the components of other comprehensive income (loss) for the three months ended March 31, 2018 and 2017, including the amount of income tax expense (benefit) allocated to each component of other comprehensive income (loss).
 
Three Months Ended March 31,
(in millions)
2018
 
2017
Accumulated net unrealized losses on investment securities:
 
 
 
Balance at beginning of period, net of tax
$
(101
)
 
$
(33
)
 
 
 
 
Cumulative effect of change in accounting principle
1

 
—

 
 
 
 
Net unrealized holding losses arising during the period
(142
)
 
(2
)
Less: Benefit for income taxes
(33
)
 
(1
)
Net unrealized holding losses arising during the period, net of tax
(109
)
 
(1
)
Less:
 
 
 
Reclassification adjustment for net losses realized as a yield adjustment included in net income, net of tax
—

 
(1
)
Change in net unrealized losses on investment securities, net of tax
(109
)
 
—

Balance at end of period, net of tax
$
(209
)
 
$
(33
)
 
 
 
 
Accumulated defined benefit pension and other postretirement plans adjustment:
 
 
 
Balance at beginning of period, net of tax
$
(350
)
 
$
(350
)
 
 
 
 
Amortization of actuarial net loss
15

 
13

Amortization of prior service credit
(7
)
 
(7
)
Amounts recognized in other noninterest expense
8

 
6

   Less: Provision for income taxes
2

 
2

Change in defined benefit pension and other postretirement plans adjustment, net of tax
6

 
4

Balance at end of period, net of tax
$
(344
)
 
$
(346
)
Total accumulated other comprehensive loss at end of period, net of tax
$
(553
)
 
$
(379
)