Consolidated Statements of Shareholders' Equity (Parenthetical) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Treasury Stock, Value	[1]	$ (3,591)	$ (2,346)
Common stock dividends, per share		$ 1.32	$ 1.00	$ 0.92
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net			$ (4)
Treasury Stock and Other
Treasury Stock, Value		$ (3,694)	(2,448)	$ (1,764)
Deferred Compensation Equity		0	(1)	(2)
Stockholders' Equity Attributable to Noncontrolling Interest		$ 103	$ 103	$ 108
Series A Preferred Stock [Member]
Preferred Stock, Dividends, Per Share, Cash Paid		$ 4,056	$ 4,067	$ 4,056
Series B Preferred Stock [Member]
Preferred Stock, Dividends, Per Share, Cash Paid		4,056	4,067	4,056
Series E Preferred Stock [Member]
Preferred Stock, Dividends, Per Share, Cash Paid		5,875	5,875	5,875
Series F Preferred Stock [Member]
Preferred Stock, Dividends, Per Share, Cash Paid		5,625	$ 5,625	$ 6,219
Series G Preferred Stock [Member]
Preferred Stock, Dividends, Per Share, Cash Paid		3,128
Series H Preferred Stock [Member]
Preferred Stock, Dividends, Per Share, Cash Paid		$ 669

[1] At December 31, 2017, includes ($3,694) million for treasury stock and $103 million for noncontrolling interest.At December 31, 2016, includes ($2,448) million for treasury stock, ($1) million for the compensation element of restricted stock, and $103 million for noncontrolling interest.At December 31, 2015, includes ($1,764) million for treasury stock,($2) million for the compensation element of restricted stock, and $108 million for noncontrolling interest.