Share-Based Compensation Long Term Incentive Plan (Details) - USD ($) $ / shares in Units, $ in Millions								1 Months Ended					3 Months Ended			12 Months Ended
	Apr. 27, 2017	Apr. 26, 2017	Apr. 28, 2016	Apr. 27, 2016	Apr. 23, 2015	Apr. 22, 2015	Apr. 03, 2014	Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2015	Feb. 28, 2014	Feb. 28, 2013	Dec. 31, 2017	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU Conversion Ratio													$ 1.17
PLC Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum Shares Available for Grant under PLC LTIP					25,665,448
PLC Long Term Incentive Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-Based Awards Payout % Range																0.00%
PLC Long Term Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-Based Awards Payout % Range																200.00%
PLC Long Term Incentive Plan | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU's Granted																1,245,000	1,219,000	1,683,000
Grant Date Fair Value								$ 63	$ 48	$ 76	$ 53	$ 60
Time-Based Awards % Granted For Officers																25.00%
Time-Based Awards % Granted For Executives																50.00%
Performance-Based Awards % Granted For Officers																75.00%
Performance-Based Awards % Granted For Executives																50.00%
PLC Long Term Incentive Plan | Restricted Stock Units (RSUs) | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU's Granted	26,782		27,238		20,347		24,144
Grant Date Fair Value	$ 2		$ 2		$ 2		$ 2
RSU's, Issued in Period, Gross		26,580		24,542		24,482
Fair Value of RSU’s Vested in Period		$ 2		$ 2		$ 2
RSU's, Used to Pay Witholding Taxes		(3,472)		(1,843)		(2,673)
PLC Long Term Incentive Plan | Restricted Stock Units (RSUs) | Executives | 2013 Grant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU's Granted												1,450,000
PLC Long Term Incentive Plan | Restricted Stock Units (RSUs) | Executives | 2014 Grant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU's Granted											780,000
PLC Long Term Incentive Plan | Restricted Stock Units (RSUs) | Executives | 2015 Grant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU's Granted										900,000
PLC Long Term Incentive Plan | Restricted Stock Units (RSUs) | Executives | 2016 Grant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU's Granted									710,000
PLC Long Term Incentive Plan | Restricted Stock Units (RSUs) | Executives | 2017 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU's Granted								800,000
PLC Long Term Incentive Plan | Restricted Stock Units (RSUs) | Executives | Time-Based
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU's, Issued in Period, Gross								248,008	395,744	535,345
Fair Value of RSU’s Vested in Period								$ 19	$ 24	$ 42
RSU's, Used to Pay Witholding Taxes								88,807	(146,726)	(199,211)
PLC Long Term Incentive Plan | Restricted Stock Units (RSUs) | Executives | Performance-Based | 2012 Grant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU's, Issued in Period, Gross															1,364,966
Fair Value of RSU’s Vested in Period															$ 107
RSU's, Used to Pay Witholding Taxes															(545,192)
PLC Long Term Incentive Plan | Restricted Stock Units (RSUs) | Executives | Performance-Based | 2013 Grant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU's, Issued in Period, Gross														797,210	1,265,339
Fair Value of RSU’s Vested in Period														$ 60	$ 77
RSU's, Used to Pay Witholding Taxes														324,555	(512,371)