|
Quarterly Financial Data (Details Textuals) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | 12 Months Ended | 3 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2014
|
Sep. 30, 2014
|
Jun. 30, 2014
|
Mar. 31, 2014
|
Dec. 31, 2013
|
Sep. 30, 2013
|
Jun. 30, 2013
|
Mar. 31, 2013
|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
Dec. 31, 2012
|
|
| Quarterly Financial Data (Textuals) [Abstract] | ||||||||||||
| Earnings allocated to participating share awards | $ 11 | $ 11 | $ 12 | $ 12 | $ 11 | $ 12 | $ 13 | $ 11 | $ 46 | $ 47 | $ 49 | |
| Periods in the prior year [Member] | ||||||||||||
| Statement [Line Items] | ||||||||||||
| Card Member reimbursements | 0 | |||||||||||
| Periods prior to the prior year [Member] | ||||||||||||
| Statement [Line Items] | ||||||||||||
| Card Member reimbursements | $ 0 | |||||||||||