Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		0 Months Ended	1 Months Ended	2 Months Ended	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	May 03, 2012 Dividend Declared [Member]	May 23, 2012 Dividend Declared [Member]	Jun. 20, 2012 Dividend Declared [Member]	Mar. 31, 2012 Common Stock [Member]	Mar. 31, 2011 Common Stock [Member]	Mar. 31, 2012 Treasury Stock [Member]	Mar. 31, 2011 Treasury Stock [Member]	Mar. 31, 2012 Parent [Member]	Mar. 31, 2011 Parent [Member]	Mar. 31, 2012 Noncontrolling Interest [Member]	Mar. 31, 2011 Noncontrolling Interest [Member]
Reconciliation of the beginning and ending balances of the carrying amount of equity
Balance at beginning of period	$ 16,445	$ 15,025								$ 16,423	$ 15,025	$ 22	$ 0
Net income (loss)	(432)	98								(432)	98	0	0
Dividends	(83)	(28)								(83)	(28)	0	0
Stock-based compensation expense	10	12								10	12	0	0
Tax deduction in excess of stock-based compensation expense	2	5								2	5	0	0
Transactions in connection with stock-based compensation plans:
Stock issuances	9	21								9	21	0	0
Stock repurchases	(95)	0								(95)	0	0	0
Contributions from noncontrolling interest	11	0								0	0	11	0
Other comprehensive income	125	91								125	91	0	0
Balance at end of period	$ 15,992	$ 15,224								$ 15,959	$ 15,224	$ 33	$ 0
Share Activity Rollforward
Common stock, shares, beginning balance						673,000,000	673,000,000
Treasury stock, shares, beginning balance	(116,689,450)							(117,000,000)	(105,000,000)
Stock issuances, stock-based compensation						0	0	1,000,000	2,000,000
Stock purchases, stock-based compensation								(5,000,000)	0
Common stock, shares, ending balance						673,000,000	673,000,000
Treasury Stock, shares, ending balance	(120,526,015)							(121,000,000)	(103,000,000)
Equity (Textual)
Dividends payable, date declared			May 03, 2012
Dividends payable, amount per share					$ 0.15
Dividends payable, date to be paid					Jun. 20, 2012
Dividends payable, date of record				May 23, 2012