Computation of Basic/Diluted Earnings Per Common Share (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Unvested restricted stock rights participating in earnings	3	9	3	10
Performance shares not included in dilutive shares (performance measures not yet met)	10	3	10	3
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted earnings per share (in shares)	4	1	4	6