Equity, Stock Related Disclosures (Details) - USD ($)		1 Months Ended	12 Months Ended
	Jan. 21, 2016	Jan. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Activity Rollforward
Treasury stock, beginning balance		(200,462,208)	(159,202,872)
Transactions in connection with stock-based compensation plans:
Treasury stock, ending balance			(200,462,208)	(159,202,872)
Equity (Textual)
Preferred stock, shares authorized			20,000,000
Preferred stock, par value per share			$ 0.01
Subsequent Event [Member]
Transactions in connection with stock-based compensation plans:
Stock purchases		(347,438)
Dividend Declared [Member] | Subsequent Event [Member]
Equity (Textual)
Dividends payable, date declared	Jan. 21, 2016
Dividends payable, amount per share	$ 0.60
Dividends payable, date to be paid	Mar. 03, 2016
Dividends payable, date of record	Feb. 09, 2016
Stock-Based Compensation Plans Repurchase Program [Member]
Equity (Textual)
Stock repurchases under buyback program			$ 196,000,000	$ 128,000,000	$ 236,000,000
Common Stock Repurchase Program [Member]
Equity (Textual)
Stock repurchases under buyback program			2,667,000,000	$ 1,168,000,000	$ 692,000,000
$3 Billion Program Approved February 2008 [Member]
Equity (Textual)
Authorized amount under stock purchase program			3,000,000,000
$6 Billion Program Previously Authorized [Member]
Equity (Textual)
Authorized amount under stock purchase program			6,000,000,000
Stock Repurchase Program Approved July 2015 [Member]
Equity (Textual)
Authorized amount under stock purchase program			2,500,000,000
Remaining amount authorized under stock purchase programs			$ 1,300,000,000
Common Stock [Member]
Share Activity Rollforward
Common stock, beginning balance		673,000,000	673,000,000	673,000,000	673,000,000
Transactions in connection with stock-based compensation plans:
Stock issuances			0	0	0
Common stock, ending balance			673,000,000	673,000,000	673,000,000
Treasury Stock [Member]
Share Activity Rollforward
Treasury stock, beginning balance		(200,000,000)	(159,000,000)	(138,000,000)	(121,000,000)
Transactions in connection with stock-based compensation plans:
Stock issuances			4,000,000	4,000,000	6,000,000
Treasury stock, ending balance			(200,000,000)	(159,000,000)	(138,000,000)
Treasury Stock [Member] | Stock-Based Compensation Plans Repurchase Program [Member]
Transactions in connection with stock-based compensation plans:
Stock purchases			(3,000,000)	(2,000,000)	(6,000,000)
Equity (Textual)
Stock repurchases under buyback program			$ 196,000,000	$ 128,000,000	$ 236,000,000
Treasury Stock [Member] | Common Stock Repurchase Program [Member]
Transactions in connection with stock-based compensation plans:
Stock purchases			(42,000,000)	(23,000,000)	(17,000,000)
Equity (Textual)
Stock repurchases under buyback program			$ 2,667,000,000	$ 1,168,000,000	$ 692,000,000