Consolidated Statements of Equity (USD $) In Millions, unless otherwise specified	Total	Parent [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
Beginning balance at Dec. 31, 2009	$ 14,725	$ 14,725	$ 7	$ 7,896	$ (6,721)	$ 13,178	$ 365	$ 0
Increase (Decrease) in Equity Roll Forward
Net income	324	324	0	0	0	324	0	0
Dividends on common stock	(114)	(114)	0	0	0	(114)	0	0
Stock-based compensation expense	54	54	0	54	0	0	0	0
Tax deduction in excess of stock-based compensation expense	6	6	0	6	0	0	0	0
Transactions in connection with stock-based compensation plans:
Stock issuances	20	20	0	(252)	272	0	0	0
Stock repurchases	(13)	(13)	0	0	(13)	0	0	0
Other comprehensive income (loss)	23	23	0	0	0	0	23	0
Ending balance at Dec. 31, 2010	15,025	15,025	7	7,704	(6,462)	13,388	388	0
Increase (Decrease) in Equity Roll Forward
Net income	2,089	2,090	0	0	0	2,090	0	(1)
Dividends on common stock	(169)	(169)	0	0	0	(169)	0	0
Stock-based compensation expense	57	57	0	57	0	0	0	0
Tax deduction in excess of stock-based compensation expense	22	22	0	22	0	0	0	0
Transactions in connection with stock-based compensation plans:
Stock issuances	49	49	0	(287)	336	0	0	0
Stock repurchases	(359)	(359)	0	(10)	(349)	0	0	0
Contributions from noncontrolling interest	23	0	0	0	0	0	0	23
Recognition of noncontrolling interests in MLP in connection with Pembroke Acquisition	5	0	0	0	0	0	0	5
Acquisition of noncontrolling interests in MLP	(5)	0	0	0	0	0	0	(5)
Other comprehensive income (loss)	(292)	(292)	0	0	0	0	(292)	0
Ending balance at Dec. 31, 2011	16,445	16,423	7	7,486	(6,475)	15,309	96	22
Increase (Decrease) in Equity Roll Forward
Net income	2,080	2,083	0	0	0	2,083	0	(3)
Dividends on common stock	(360)	(360)	0	0	0	(360)	0	0
Stock-based compensation expense	57	57	0	57	0	0	0	0
Tax deduction in excess of stock-based compensation expense	29	29	0	29	0	0	0	0
Transactions in connection with stock-based compensation plans:
Stock issuances	59	59	0	(260)	319	0	0	0
Stock repurchases	(153)	(153)	0	10	(163)	0	0	0
Stock repurchases under buyback program	(118)	(118)	0	0	(118)	0	0	0
Contributions from noncontrolling interest	44	0	0	0	0	0	0	44
Other comprehensive income (loss)	12	12	0	0	0	0	12	0
Ending balance at Dec. 31, 2012	$ 18,095	$ 18,032	$ 7	$ 7,322	$ (6,437)	$ 17,032	$ 108	$ 63