CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Millions, unless otherwise specified	Total	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	RETAINED EARNINGS
Balance at Dec. 31, 2012		$ 626	$ 19,079	$ (1,701)	$ 1,285
Increase (Decrease) in Stockholders' Equity
Issuance of common stock through dividend reinvestment, incentive and benefit plans		2	38
Repurchase of common stock		(24)	(845)
Shares withheld to satisfy tax withholdings			(16)
Share-based compensation and other, net			35
Other comprehensive income	13			13
Net income	567				567
Dividends declared			0		(659)
Balance at Jun. 30, 2013	18,400	604	18,291	(1,688)	1,193
Balance at Dec. 31, 2013	17,191	584	17,343	(802)	66
Increase (Decrease) in Stockholders' Equity
Issuance of common stock through dividend reinvestment, incentive and benefit plans		2	30
Repurchase of common stock		(15)	(441)
Shares withheld to satisfy tax withholdings			(14)
Share-based compensation and other, net			42
Other comprehensive income	23			23
Net income	396				396
Dividends declared			(289)		(327)
Balance at Jun. 30, 2014	$ 16,598	$ 571	$ 16,671	$ (779)	$ 135